Incompleteness

Representability in Q

Equation form expr-002bf3eb1573e012

k+1k+1

Read as: k plus one

Means: k plus one

Equation form expr-00acf7ce579f67f3

Azero(x,y)y=0!A_{\Zero}(x,y) \ident \eq[y][\Obj 0]

Read as: A subscript zero function of x and y is the formula y equals the object language constant zero

Means: A subscript zero function of x and y is the formula y equals the object language constant zero

Equation form expr-00cf750d9cce40d2

Q¬A(n¯)\Th{Q} \Proves \lnot !A(\num{n})

Read as: Q proves that not A of the numeral for n

Means: Q proves that not A of the numeral for n

Equation form expr-00e3b80d5a90664e

Af(z,y)Ag(y,z,0)w(w<y¬Ag(w,z,0)).!A_f(z,y) \ident !A_g(y, z, \Obj 0) \land \lforall[w][(w < y \lif \lnot !A_g(w, z, \Obj 0))].

Read as: A subscript f of z and y is the conjunction of A subscript g of y, z, and the object language constant zero, with the following universal statement: for every w, if w is less than y then not A subscript g of w, z, and the object language constant zero

Means: A subscript f of z and y is the conjunction of A subscript g of y, z, and the object language constant zero, with the following universal statement: for every w, if w is less than y then not A subscript g of w, z, and the object language constant zero

Equation form expr-00fe9b383f124db5

yny_n

Read as: y subscript n

Means: y subscript n

Equation form expr-0120f8b6ce4d3c14

(b+a)=0\eq[(b'+a)][\Obj 0]

Read as: the sum of the successor of b and a equals the object language constant zero

Means: the sum of the successor of b and a equals the object language constant zero

Equation form expr-0180ff76ea2f422f

h(x,y)=β(h^(x,y),y),h(\vec x, y) = \beta(\hat h(\vec x, y), y),

Read as: h of the tuple x and y equals beta of h hat of the tuple x and y, and y

Means: h of the tuple x and y equals beta of h hat of the tuple x and y, and y

Equation form expr-02d48ad3da1936b3

z+t1=t2\eq[z' + t_1][t_2]

Read as: the sum of the successor of z and t subscript one equals t subscript two

Means: the sum of the successor of z and t subscript one equals t subscript two

Equation form expr-033c668a4e2817cd

ProvQ(y)Sent(y)xPrfQ(x,y)\Prov[\Th{Q}](y) \defiff \fn{Sent}(y) \land \lexists[x][\Prf[\Th{Q}](x, y)]

Read as: Provability in Q holds of y by definition if and only if y is a sentence code and there exists x which codes a derivation in Q of the formula with code y

Means: Provability in Q holds of y by definition if and only if y is a sentence code and there exists x which codes a derivation in Q of the formula with code y

Equation form expr-0343067284e5822a

AxB(x)!A \ident \lexists[x][!B(x)]

Read as: A is the formula there exists x such that B of x

Means: A is the formula there exists x such that B of x

Equation form expr-03601b0ecb040012

(b+c)=0\eq[(b' + c)'][\Obj 0]

Read as: the successor of the sum of the successor of b and c equals the object language constant zero

Means: the successor of the sum of the successor of b and c equals the object language constant zero

Equation form expr-0407f4d79a43a272

mult(x0,x1)=x0·x1\Mult(x_0, x_1) = x_0 \cdot x_1

Read as: the multiplication function applied to x subscript zero and x subscript one equals x subscript zero times x subscript one

Means: the multiplication function applied to x subscript zero and x subscript one equals x subscript zero times x subscript one

Equation form expr-043a718774c572bd

ss

Read as: s

Means: s

Equation form expr-043e4702cf309ada

QAh(n¯,m¯)\Th{Q} \Proves !A_h(\num{n}, \num{m})

Read as: Q proves that A subscript h of the numeral for n and the numeral for m

Means: Q proves that A subscript h of the numeral for n and the numeral for m

Equation form expr-0459187f686800bb

(z+nm1¯)=0\eq[(z' + \num{n - m - 1})'][\Obj 0]

Read as: the successor of the sum of the successor of z and the numeral for n minus m minus one equals the object language constant zero

Means: the successor of the sum of the successor of z and the numeral for n minus m minus one equals the object language constant zero

Equation form expr-046ab677882f254d

nkn \neq k

Read as: n does not equal k

Means: n does not equal k

Equation form expr-046b4724fc2febf0

ana_n

Read as: a subscript n

Means: a subscript n

Equation form expr-046becba09a52afb

Qw(w<m¯¬Ag(w,n¯,0))\Th{Q} \Proves \lforall[w][(w < \num{m} \lif \lnot !A_g(w, \num{n}, \Obj 0))]

Read as: Q proves that for every w, if w is less than the numeral for m then not A subscript g of w, the numeral for n, and the object language constant zero

Means: Q proves that for every w, if w is less than the numeral for m then not A subscript g of w, the numeral for n, and the object language constant zero

Equation form expr-07587fdd1bdb1d42

ValN((t1+t2))=ValN(t1)+ValN(t2)=n1+n2.\Value{(t_1 + t_2)}{N} = \Value{t_1}{N} + \Value{t_2}{N} = n_1 + n_2.

Read as: The value of the term t subscript one plus t subscript two in the standard model N equals the value of t subscript one in N plus the value of t subscript two in N. This equals n subscript one plus n subscript two

Means: The value of the term t subscript one plus t subscript two in the standard model N equals the value of t subscript one in N plus the value of t subscript two in N. This equals n subscript one plus n subscript two

Equation form expr-08a31aaffef905c3

xnx_n

Read as: x subscript n

Means: x subscript n

Equation form expr-08c6aa8d5824f2de

succ\Succ

Read as: the successor function

Means: the successor function

Equation form expr-0916713022826be9

A=(n¯,m¯,1¯)!A_=(\num{n}, \num{m}, \num{1})

Read as: A subscript equality applied to the numerals for n and m, and the numeral for one

Means: A subscript equality applied to the numerals for n and m, and the numeral for one

Equation form expr-099959186b7f6cac

n=mn = m

Read as: n equals m

Means: n equals m

Equation form expr-09bda5125a2f9e49

QAf(n0¯,,nk¯,m¯)iffm=f(n0,,nk).\Th{Q} \Proves !A_f(\num{n_0}, \dots, \num{n_k}, \num{m}) \quad\text{iff}\quad m = f(n_0, \dots, n_k).

Read as: Q proves A subscript f applied to the numerals for n subscript zero through n subscript k, and the numeral for m, if and only if m equals f of n subscript zero through n subscript k

Means: Q proves A subscript f applied to the numerals for n subscript zero through n subscript k, and the numeral for m, if and only if m equals f of n subscript zero through n subscript k

Equation form expr-09f5d3cdd4f61799

p1+(i+1)mp \mid 1 + (i+1) m

Read as: p divides one plus the product of i plus one and m

Means: p divides one plus the product of i plus one and m

Equation form expr-0a2c809e671649ae

h^(x,y)\hat h(\vec x, y)

Read as: h hat of the tuple x and y

Means: h hat of the tuple x and y

Equation form expr-0a566b1db5acde7f

g0g_0

Read as: g subscript zero

Means: g subscript zero

Equation form expr-0a5a0cdb7119bde3

nmn \neq m

Read as: n does not equal m

Means: n does not equal m

Equation form expr-0a731ae7784bab75

R(n0,,nk,s)R(n_0, \dots, n_k, s)

Read as: R of n subscript zero through n subscript k, and s

Means: R of n subscript zero through n subscript k, and s

Equation form expr-0aaed6339b81f11f

j=max(n,y0+1,,yn+1),m=lcm(1,,j),j &= \max(n, y_0 + 1, \dots, y_n + 1), \\ m &= \lcm(1,\dots,j),

Read as: j equals the maximum of n, y subscript zero plus one, and so on through y subscript n plus one. m equals the least common multiple of the integers one through j

Means: j equals the maximum of n, y subscript zero plus one, and so on through y subscript n plus one. m equals the least common multiple of the integers one through j

Equation form expr-0ac6f2ec0fc75966

k¯\num{k}

Read as: the numeral for k

Means: the numeral for k

Equation form expr-0b0fc5327dcecbe2

a<1¯a < \num 1

Read as: a is less than the numeral for one

Means: a is less than the numeral for one

Equation form expr-0b9c5e137bc7261e

h(n)=mh(n) = m

Read as: h of n equals m

Means: h of n equals m

Equation form expr-0bde84c13896897b

x<k+1¯x < \num{k+1}

Read as: x is less than the numeral for k plus one

Means: x is less than the numeral for k plus one

Equation form expr-0c121de460f446f8

(x<t)¬A(x)\bforall{x<t}{\lnot!A(x)}

Read as: for every x less than t, not A of x

Means: for every x less than t, not A of x

Equation form expr-0c46538005b57adc

Ag(x,y)!A_g(x, y)

Read as: A subscript g of x and y

Means: A subscript g of x and y

Equation form expr-0c6150bf3a95a786

mnm \leq n

Read as: m is less than or equal to n

Means: m is less than or equal to n

Equation form expr-0c615cfc75a63a7d

h(x,0)=f(x)h(x,y+1)=g(x,y,h(x,y)).h(\vec x, 0) & = f(\vec x) \\ h(\vec x, y+1) & = g(\vec x, y, h(\vec x, y)).

Read as: Base case: h of the tuple x and zero equals f of the tuple x. Recursion step: h of the tuple x and y plus one equals g of the tuple x, y, and h of the tuple x and y

Means: Base case: h of the tuple x and zero equals f of the tuple x. Recursion step: h of the tuple x and y plus one equals g of the tuple x, y, and h of the tuple x and y

Equation form expr-0ca087e027fea4f9

Aadd(x0,x1,y)y=(x0+x1).!A_{\Add}(x_0, x_1, y) \ident \eq[y][(x_0 + x_1)].

Read as: A subscript Add of x subscript zero, x subscript one, and y is the formula y equals the sum of x subscript zero and x subscript one

Means: A subscript Add of x subscript zero, x subscript one, and y is the formula y equals the sum of x subscript zero and x subscript one

Equation form expr-0e895da1dde0af8b

yi<jm<xiy_i < j \leq m < x_i

Read as: y subscript i is less than j; j is less than or equal to m; and m is less than x subscript i

Means: y subscript i is less than j; j is less than or equal to m; and m is less than x subscript i

Equation form expr-0ef4b2cb1fbfa584

xyx=yx=y\lforall[x][\lforall[y][\eq[x'][y'] \lif \eq[x][y]]]

Read as: for all x and y, if their successors are equal, then x equals y

Means: for all x and y, if their successors are equal, then x equals y

Equation form expr-0ef721aef4e4d1c4

Qy(Af(n¯,y)y=m¯)\Th{Q} \Proves \lforall[y][(!A_f(\num{n}, y) \lif \eq[y][\num{m}])]

Read as: Q proves that for every y, if A subscript f holds of the numeral for n and y, then y equals the numeral for m

Means: Q proves that for every y, if A subscript f holds of the numeral for n and y, then y equals the numeral for m

Equation form expr-0f54ca49553849bd

z0\eq/[z'][\Obj 0]

Read as: the successor of z does not equal the object language constant zero

Means: the successor of z does not equal the object language constant zero

Equation form expr-0f6a28bdfad5c884

f(y0,,yk1)f(y_0, \dots, y_{k-1})

Read as: f of y subscript zero through y subscript k minus one

Means: f of y subscript zero through y subscript k minus one

Equation form expr-10ae1238b3bedd73

m+1¯\num{m+1}

Read as: the numeral for m plus one

Means: the numeral for m plus one

Equation form expr-10d29b12563e1ccd

Ag(x,z,y)!A_g(x, z, y)

Read as: A subscript g of x, z, and y

Means: A subscript g of x, z, and y

Equation form expr-115ce48a5e1e2710

|ik|\left|i-k\right|

Read as: the absolute value of i minus k

Means: the absolute value of i minus k

Equation form expr-116a126b4adf26eb

y(y+a)=0\lexists[y][\eq[(y'+a)][\Obj 0]]

Read as: there exists y such that the sum of the successor of y and a equals the object language constant zero

Means: there exists y such that the sum of the successor of y and a equals the object language constant zero

Equation form expr-11baa595827a4e0f

ω\omega

Read as: omega

Means: omega

Equation form expr-126ba9dbf35ba818

Qk¯+t1=t2\Th{Q} \Proves \eq[{\num k}' + t_1][t_2]

Read as: Q proves that the sum of the successor of the numeral for k and t subscript one equals t subscript two

Means: Q proves that the sum of the successor of the numeral for k and t subscript one equals t subscript two

Equation form expr-12d9b1e9f8e5096a

N,sA(x)\Sat{N}{!A(x)}[s]

Read as: the standard model N under assignment s satisfies A of x

Means: the standard model N under assignment s satisfies A of x

Equation form expr-139c7c04318de35e

n=0n = 0

Read as: n equals zero

Means: n equals zero

Equation form expr-13b7fc57566924a3

Ql¯=m¯\Th{Q} \Proves \eq[\num{l}][\num{m}]

Read as: Q proves that the numeral for l equals the numeral for m

Means: Q proves that the numeral for l equals the numeral for m

Equation form expr-13dcd97896f4422a

succ(x)=x+1\Succ(x) = x+1

Read as: the successor function applied to x equals x plus one

Means: the successor function applied to x equals x plus one

Equation form expr-147d8c41e77101cc

Qx(x<n+1¯(x=0x=n¯)).\Th{Q} \Proves \lforall[x][(x < \num {n+1} \lif (\eq[x][\Obj 0] \lor \dots \lor \eq[x][\num n]))].

Read as: Q proves that for every x, if x is less than the numeral for n plus one, then x equals one of the numerals from zero through n

Means: Q proves that for every x, if x is less than the numeral for n plus one, then x equals one of the numerals from zero through n

Equation form expr-148de9c5a7a44d19

pp

Read as: p

Means: p

Equation form expr-149bf3c439e010d6

c<0c < \Obj 0

Read as: c is less than the object language constant zero

Means: c is less than the object language constant zero

Equation form expr-14adae10a93f394c

Aadd(x0,x1,y)!A_\Add(x_0, x_1, y)

Read as: A subscript Add applied to x subscript zero, x subscript one, and y

Means: A subscript Add applied to x subscript zero, x subscript one, and y

Equation form expr-152fd4c0c212fbe9

ValN(t2)ValN(t1)\Value{t_2}{N} \leq \Value{t_1}{N}

Read as: the value of t subscript two in the standard model N is less than or equal to the value of t subscript one in the standard model N

Means: the value of t subscript two in the standard model N is less than or equal to the value of t subscript one in the standard model N

Equation form expr-1581d72466c85316

xkx_k

Read as: x subscript k

Means: x subscript k

Equation form expr-15fd307d7f46f8c3

2¯\num{2}

Read as: the numeral for two

Means: the numeral for two

Equation form expr-16905e3dcc56a2ae

Q(n¯+m¯)=n+m¯\Th{Q} \Proves \eq[(\num{n} + \num{m}')][\num{n+m}']

Read as: Q proves that the sum of the numeral for n and the successor of the numeral for m equals the successor of the numeral for n plus m

Means: Q proves that the sum of the numeral for n and the successor of the numeral for m equals the successor of the numeral for n plus m

Equation form expr-173061a6aaa446d4

QA=(n¯,m¯,0¯)\Th{Q} \Proves !A_=(\num{n}, \num{m}, \num{0})

Read as: Q proves that A subscript equality applied to the numerals for n and m, and the numeral for zero

Means: Q proves that A subscript equality applied to the numerals for n and m, and the numeral for zero

Equation form expr-188f5e8c4839a80f

b<n+2¯b' < \num {n+2}

Read as: the successor of b is less than the numeral for n plus two

Means: the successor of b is less than the numeral for n plus two

Equation form expr-18ac3e7343f01689

dd

Read as: d

Means: d

Equation form expr-18e9a2ef1c0f5cb1

(c+m¯)=b\eq[(c' + \num{m}')][b']

Read as: the sum of the successor of c and the successor of the numeral for m equals the successor of b

Means: the sum of the successor of c and the successor of the numeral for m equals the successor of b

Equation form expr-18ef0ae4db587e5b

QyA(y)\Th{Q} \Proves/ \lexists[y][!A(y)]

Read as: Q does not prove that there exists y such that A of y

Means: Q does not prove that there exists y such that A of y

Equation form expr-18fb187f6340634b

Qt2=n¯\Th{Q} \Proves \eq[t_2][\num n]

Read as: Q proves that t subscript two equals the numeral for n

Means: Q proves that t subscript two equals the numeral for n

Equation form expr-1922c19949fdd3f1

(x<t)A(x)\bexists{x < t}{!A(x)}

Read as: there exists x less than t such that A of x

Means: there exists x less than t such that A of x

Equation form expr-19b2a8c282eaa008

rem(x,y)\fn{rem}(x,y)

Read as: rem of x and y, the remainder when y is divided by x

Means: rem of x and y, the remainder when y is divided by x

Equation form expr-19e9c269d8cb4bcf

s(x)=ns(x) = n

Read as: assignment s sends x to n

Means: assignment s sends x to n

Equation form expr-1b16b1df538ba12d

nn

Read as: n

Means: n

Equation form expr-1b8ddd311995c3e6

Ql¯m¯\Th{Q} \Proves \eq/[\num{l}][\num{m}]

Read as: Q proves that the numeral for l does not equal the numeral for m

Means: Q proves that the numeral for l does not equal the numeral for m

Equation form expr-1ba1ebd4a3e5f2fa

(x<t)¬A(x)\bexists{x<t}{\lnot !A(x)}

Read as: there exists x less than t such that not A of x

Means: there exists x less than t such that not A of x

Equation form expr-1bf0def65cbf1cdf

f(g(n))=mf(g(n)) = m

Read as: f of g of n equals m

Means: f of g of n equals m

Equation form expr-1ebbf9f57552ec69

m=f(n0,,nk)m = f(n_0, \dots, n_k)

Read as: m equals f of n subscript zero through n subscript k

Means: m equals f of n subscript zero through n subscript k

Equation form expr-1f0b48345ddedcf2

z0z_0

Read as: z subscript zero

Means: z subscript zero

Equation form expr-1f3ab9cf428562d8

QA(0¯)A(k1¯)\Th{Q} \Proves !A(\num 0) \lor \dots \lor !A(\num{k-1})

Read as: Q proves that the finite disjunction of A applied to each numeral from zero through k minus one

Means: Q proves that the finite disjunction of A applied to each numeral from zero through k minus one

Equation form expr-1f97d653b7ed2d2b

n+1n+1

Read as: n plus one

Means: n plus one

Equation form expr-20aa50a3a1186f9b

abmodca \equiv b \mod c

Read as: a is congruent to b modulo c

Means: a is congruent to b modulo c

Equation form expr-20b07e4823cb2fb8

#yBT(e¯,n¯,y)#\Gn{\lexists[y][!B_T(\num{e}, \num{n}, y)]}

Read as: the Goedel number of the formula there exists y such that B subscript T holds of the numeral for e, the numeral for n, and y

Means: the Goedel number of the formula there exists y such that B subscript T holds of the numeral for e, the numeral for n, and y

Equation form expr-2243b195c00d21fb

BT!B_T

Read as: B subscript T

Means: B subscript T

Equation form expr-22ced2a4d81d280b

QAf(n¯,m¯)\Th{Q} \Proves !A_f(\num n, \num m)

Read as: Q proves that A subscript f of the numeral for n and the numeral for m

Means: Q proves that A subscript f of the numeral for n and the numeral for m

Equation form expr-23146883045d970e

m¯\num m

Read as: the numeral for m

Means: the numeral for m

Equation form expr-2340230b2e0abc21

ValN(0)=0\Value{\Obj 0}{N} = 0

Read as: the value of the object language constant zero in the standard model N equals zero

Means: the value of the object language constant zero in the standard model N equals zero

Equation form expr-234ef32b30394a54

(AB)(!A \lor !B)

Read as: the disjunction of A and B

Means: the disjunction of A and B

Equation form expr-2355ecda4c890c45

(1+(i+1)m)(1+(k+1)m)=(ik)m.(1 + (i+1)m) - (1+ (k+1)m) = (i-k) m.

Read as: the quantity one plus the product of i plus one and m, minus the quantity one plus the product of k plus one and m, equals the product of i minus k and m

Means: the quantity one plus the product of i plus one and m, minus the quantity one plus the product of k plus one and m, equals the product of i minus k and m

Equation form expr-236a9900efeb2107

a=b\eq[a][b']

Read as: a equals the successor of b

Means: a equals the successor of b

Equation form expr-241d658a47ae5a64

a0a_0

Read as: a subscript zero

Means: a subscript zero

Equation form expr-24931e0795a913c5

Asucc(x,y)y=x!A_{\Succ}(x,y) \ident \eq[y][x']

Read as: A subscript successor function of x and y is the formula y equals the successor of x

Means: A subscript successor function of x and y is the formula y equals the successor of x

Equation form expr-250dc58ba799c9f2

b<n+1¯b' < \num{n+1}'

Read as: the successor of b is less than the successor of the numeral for n plus one

Means: the successor of b is less than the successor of the numeral for n plus one

Equation form expr-252f10c83610ebca

ff

Read as: f

Means: f

Equation form expr-25c79bc25c22b1f3

ValN(t1)<ValN(t2)\Value{t_1}{N} < \Value{t_2}{N}

Read as: the value of t subscript one in the standard model N is less than the value of t subscript two in the standard model N

Means: the value of t subscript one in the standard model N is less than the value of t subscript two in the standard model N

Equation form expr-2744a80ff53255bd

kk \in \Nat

Read as: k is a natural number

Means: k is a natural number

Equation form expr-274ec82875bc15b2

yiy_i

Read as: y subscript i

Means: y subscript i

Equation form expr-2808f40d73183bcd

f(n0,,nk)=mf(n_0,\dots,n_k) = m

Read as: f of n subscript zero through n subscript k equals m

Means: f of n subscript zero through n subscript k equals m

Equation form expr-28ec9f481d74b678

Qk¯=(n¯+m¯)\Th{Q} \Proves \eq[\num{k}][(\num{n} + \num{m})]

Read as: Q proves that the numeral for k equals the sum of the numeral for n and the numeral for m

Means: Q proves that the numeral for k equals the sum of the numeral for n and the numeral for m

Equation form expr-290f81ef5dc5dcca

h^\hat h

Read as: h hat

Means: h hat

Equation form expr-29123983a0cb6d1b

z=f(y)z = f(y)

Read as: z equals f of y

Means: z equals f of y

Equation form expr-2a2da3070718fdd9

Qt1+t2=n1¯+t2\Th{Q} \Proves \eq[t_1 + t_2][\num{n_1} + t_2]

Read as: Q proves that the sum of t subscript one and t subscript two equals the sum of the numeral for n subscript one and t subscript two

Means: Q proves that the sum of t subscript one and t subscript two equals the sum of the numeral for n subscript one and t subscript two

Equation form expr-2adf4f17373d7d33

Af(y,z)!A_f(y, z)

Read as: A subscript f of y and z

Means: A subscript f of y and z

Equation form expr-2c866df94f98ffce

k=g(n)k = g(n)

Read as: k equals g of n

Means: k equals g of n

Equation form expr-2cc7cd477953ceb2

u(u+b)=m+1¯\lexists[u][\eq[(u' + b')][\num{m+1}]]

Read as: there exists u such that the sum of the successor of u and the successor of b equals the numeral for m plus one

Means: there exists u such that the sum of the successor of u and the successor of b equals the numeral for m plus one

Equation form expr-2d36cab8ffd2acf4

Q¬(t1<t2)\Th{Q} \Proves \lnot(t_1 < t_2)

Read as: Q proves that it is not the case that t subscript one is less than t subscript two

Means: Q proves that it is not the case that t subscript one is less than t subscript two

Equation form expr-2d711642b726b044

xx

Read as: x

Means: x

Equation form expr-2df9d6aad7e20fb7

f(z)=μx[g(x,z)=0]f(z) = \umin{x}{[g(x, z) = 0]}

Read as: f of z equals the least x such that g of x and z equals zero

Means: f of z equals the least x such that g of x and z equals zero

Equation form expr-2e607d1da306b922

χR(x0,,xk)\Char{R}(x_0, \dots, x_k)

Read as: the characteristic function of R applied to x subscript zero through x subscript k

Means: the characteristic function of R applied to x subscript zero through x subscript k

Equation form expr-2e7d2c03a9507ae2

cc

Read as: c

Means: c

Equation form expr-2ec537e0c5458fb9

Aχ=(x0,x1,y)(x0=x1y=1¯)(x0x1y=0¯).!A_{\Char{=}}(x_0, x_1, y) \ident (\eq[x_0][x_1] \land \eq[y][\num{1}]) \lor (\eq/[x_0][x_1] \land \eq[y][\num{0}]).

Read as: A subscript characteristic function of equality, applied to x subscript zero, x subscript one, and y, is the following disjunction. Either x subscript zero equals x subscript one and y equals the numeral for one; or x subscript zero does not equal x subscript one and y equals the numeral for zero

Means: A subscript characteristic function of equality, applied to x subscript zero, x subscript one, and y, is the following disjunction. Either x subscript zero equals x subscript one and y equals the numeral for one; or x subscript zero does not equal x subscript one and y equals the numeral for zero

Equation form expr-2f02fbff196b184d

¬AχR(n0¯,,nk¯,1¯)\lnot !A_{\Char{R}}(\num{n_0}, \dots, \num{n_k}, \num{1})

Read as: not A subscript characteristic function of R, applied to the numerals for n subscript zero through n subscript k, and the numeral for one

Means: not A subscript characteristic function of R, applied to the numerals for n subscript zero through n subscript k, and the numeral for one

Equation form expr-2f6e2197f5458485

¬(x<t)A(x)\lnot \bexists{x<t}!A(x)

Read as: the negation of the bounded existential formula with variable x, bound t, and matrix A of x

Means: the negation of the bounded existential formula with variable x, bound t, and matrix A of x

Equation form expr-304c6693e2e2e163

f(x)f(\vec x)

Read as: f of the tuple x

Means: f of the tuple x

Equation form expr-3078a09641b0267f

x0x_0

Read as: x subscript zero

Means: x subscript zero

Equation form expr-30c655c7dac91d1c

0<a\Obj 0 < a

Read as: the object language constant zero is less than a

Means: the object language constant zero is less than a

Equation form expr-32521462ae8ed713

PrfQ(d,y)\Prf[\Th{Q}](d,y)

Read as: d is the Goedel number of a derivation in Q of the formula with Goedel number y

Means: d is the Goedel number of a derivation in Q of the formula with Goedel number y

Equation form expr-33136afeecc76360

n¯k¯n¯k¯\eq/[\num n][\num k] \lif \eq/[\num n'][\num k']

Read as: if the numeral for n does not equal the numeral for k, then their successors do not equal each other

Means: if the numeral for n does not equal the numeral for k, then their successors do not equal each other

Equation form expr-332ee6e9f858154b

h(x0,,xl1)=f(g0(x0,,xl1),,gk1(x0,,xl1)).h(x_0,\dots,x_{l-1}) = f(g_0(x_0,\dots,x_{l-1}), \dots, g_{k-1}(x_0,\dots,x_{l-1})).

Read as: h of x subscript zero through x subscript l minus one equals f applied to the outputs of g subscript zero through g subscript k minus one, each evaluated on that same input tuple x subscript zero through x subscript l minus one

Means: h of x subscript zero through x subscript l minus one equals f applied to the outputs of g subscript zero through g subscript k minus one, each evaluated on that same input tuple x subscript zero through x subscript l minus one

Equation form expr-33c928be6532259f

b=0b=n¯\eq[b][\Obj 0] \lor \dots \lor \eq[b][\num{n}]

Read as: b equals one of the numerals from zero through n

Means: b equals one of the numerals from zero through n

Equation form expr-349ba76d907adfab

×\times

Read as: the object language multiplication symbol

Means: the object language multiplication symbol

Equation form expr-34a408f1932d96be

xy(x+y)=(x+y)\lforall[x][\lforall[y][(x' + y) = (x + y)']]

Read as: for all x and y, the sum of the successor of x and y equals the successor of the sum of x and y

Means: for all x and y, the sum of the successor of x and y equals the successor of the sum of x and y

Equation form expr-34b6db63031b8989

Qz(Ah(n¯,z)z=m¯)\Th{Q} \Proves \lforall[z][(!A_h(\num{n}, z) \lif z = \num{m})]

Read as: Q proves that for every z, if A subscript h holds of the numeral for n and z, then z equals the numeral for m

Means: Q proves that for every z, if A subscript h holds of the numeral for n and z, then z equals the numeral for m

Equation form expr-3509c2eb7a4f4f4a

(ik)m(i-k)m

Read as: the quantity i minus k, times m

Means: the quantity i minus k, times m

Equation form expr-363cd42d5ac9f41a

gi(x0,,xl1)g_i(x_0, \dots, x_{l-1})

Read as: g subscript i of x subscript zero through x subscript l minus one

Means: g subscript i of x subscript zero through x subscript l minus one

Equation form expr-36613f93d5f91b7d

h(x)=f(g(x))h(x) = f(g(x))

Read as: h of x equals f of g of x

Means: h of x equals f of g of x

Equation form expr-369ed52f7eb96cb2

1+2d11+2 d_1

Read as: one plus two times d subscript one

Means: one plus two times d subscript one

Equation form expr-36a9ee34765ec360

Q(n¯×m¯)=n·m¯\Th{Q} \Proves \eq[(\num{n} \times \num{m})][\num{n \cdot m}]

Read as: Q proves that the object language product of the numeral for n and the numeral for m equals the numeral for n times m

Means: Q proves that the object language product of the numeral for n and the numeral for m equals the numeral for n times m

Equation form expr-36c99c0bb63416fc

gig_i

Read as: g subscript i

Means: g subscript i

Equation form expr-3748191a26c840ce

g(x,z)g(x, z)

Read as: g of x and z

Means: g of x and z

Equation form expr-3768367f8e78740f

w(w<b¬Ag(w,n¯,0))\lforall[w][(w < b \lif \lnot !A_g(w, \num{n}, \Obj 0))]

Read as: for every w, if w is less than b then not A subscript g of w, the numeral for n, and the object language constant zero

Means: for every w, if w is less than b then not A subscript g of w, the numeral for n, and the object language constant zero

Equation form expr-37a84ca5445df351

(c+b)=m¯\eq[(c' + b')][\num{m}']

Read as: the sum of the successor of c and the successor of b equals the successor of the numeral for m

Means: the sum of the successor of c and the successor of b equals the successor of the numeral for m

Equation form expr-380918b946a52664

==

Read as: equality

Means: equality

Equation form expr-38207f98f811b79b

x<0¯x<\num 0

Read as: x is less than the numeral for zero

Means: x is less than the numeral for zero

Equation form expr-3851442364e6f15c

ProvQ\Prov[\Th{Q}]

Read as: the provability relation for Q

Means: the provability relation for Q

Equation form expr-38654273862c7252

Qt1+t2=n1+n2¯\Th{Q} \Proves \eq[t_1 + t_2][\num{n_1 + n_2}]

Read as: Q proves that the sum of t subscript one and t subscript two equals the numeral for n subscript one plus n subscript two

Means: Q proves that the sum of t subscript one and t subscript two equals the numeral for n subscript one plus n subscript two

Equation form expr-393b89d1414d6ea3

Q¬BT(e¯,n¯,s¯)\Th{Q} \Proves \lnot !B_T(\num{e}, \num{n}, \num{s})

Read as: Q proves that not B subscript T applied to the numerals for e, n, and s

Means: Q proves that not B subscript T applied to the numerals for e, n, and s

Equation form expr-3a8f1b078f3f2c11

(d)0=f(x)(d)_0 = f(\vec x)

Read as: the entry beta of d and zero equals f of the tuple x

Means: the entry beta of d and zero equals f of the tuple x

Equation form expr-3ade0c4e814b7a10

β(d,i)\beta(d,i)

Read as: beta of d and i

Means: beta of d and i

Equation form expr-3b391ecd75985eba

QAf(n0¯,,nk¯,m¯)\Th{Q} \Proves !A_f(\num{n_0}, \dots, \num{n_k}, \num{m})

Read as: Q proves that A subscript f applied to the numerals for n subscript zero through n subscript k, and the numeral for m

Means: Q proves that A subscript f applied to the numerals for n subscript zero through n subscript k, and the numeral for m

Equation form expr-3cc31176550ef537

x(x<tA(x))\lexists[x][(x < t \land !A(x))]

Read as: there exists x such that both x is less than t and A of x

Means: there exists x such that both x is less than t and A of x

Equation form expr-3cd97a31b560be7d

R(x0,,xk)R(x_0,\dots,x_k)

Read as: R of x subscript zero through x subscript k

Means: R of x subscript zero through x subscript k

Equation form expr-3cdee58aaa5ae70f

xy(x+y)=(y+x)\lforall[x][\lforall[y][(x + y) = (y + x)]]

Read as: for all x and y, the sum of x and y equals the sum of y and x

Means: for all x and y, the sum of x and y equals the sum of y and x

Equation form expr-3d2df79065b6f165

Q\Th{Q}

Read as: Q

Means: Q

Equation form expr-3d8599ee1cdce5f5

Ah(x,z)!A_h(x, z)

Read as: A subscript h of x and z

Means: A subscript h of x and z

Equation form expr-3dc609ecaa989589

(x<t)A(x)\bforall{x<t}{!A(x)}

Read as: the bounded universal formula with variable x, bound t, and matrix A of x

Means: the bounded universal formula with variable x, bound t, and matrix A of x

Equation form expr-3ddc4c39050a4dea

x<yzz+x=yx < y \liff \lexists[z][\eq[z' + x][y]]

Read as: x is less than y if and only if there exists z such that the sum of the successor of z and x equals y

Means: x is less than y if and only if there exists z such that the sum of the successor of z and x equals y

Equation form expr-3dddf911c3c51204

0\Obj{0}'

Read as: the successor of the object language constant zero

Means: the successor of the object language constant zero

Equation form expr-3e23e8160039594a

bb

Read as: b

Means: b

Equation form expr-3f79bb7b435b0532

ee

Read as: e

Means: e

Equation form expr-3fedf4ba120fb495

Q(a+0)=aby axiom Q4Q(a+0)=aby axiom Q4Q(a+0)=aby step two of the successor and fixed numeral addition derivationQ(a+0)=(a+0)by step one of the successor and fixed numeral addition derivation and step three of the successor and fixed numeral addition derivation\Th{Q} & \Proves \eq[(a' + \Obj 0)][a'] \quad \text{by axiom $Q_4$} \ollabel{step1}\\ \Th{Q} & \Proves \eq[(a + \Obj 0)][a] \quad \text{by axiom $Q_4$} \ollabel{step2} \\ \Th{Q} & \Proves \eq[(a + \Obj 0)'][a'] \quad \text{by \olref{step2}} \ollabel{step3} \\ \Th{Q} & \Proves \eq[(a' + \Obj 0)][(a + \Obj 0)'] \quad \text{by \olref{step1} and \olref{step3}}\notag

Read as: Step one. Q proves that the sum of the successor of a and the object language constant zero equals the successor of a, by axiom Q subscript four. Step two. Q proves that the sum of a and that constant zero equals a, by axiom Q subscript four. Step three. Q proves that the successor of the sum of a and that constant zero equals the successor of a, by step two of the successor and fixed numeral addition derivation. Therefore Q proves that the sum of the successor of a and that constant zero equals the successor of the sum of a and that constant zero, by step one of the successor and fixed numeral addition derivation and step three of the successor and fixed numeral addition derivation

Means: Step one. Q proves that the sum of the successor of a and the object language constant zero equals the successor of a, by axiom Q subscript four. Step two. Q proves that the sum of a and that constant zero equals a, by axiom Q subscript four. Step three. Q proves that the successor of the sum of a and that constant zero equals the successor of a, by step two of the successor and fixed numeral addition derivation. Therefore Q proves that the sum of the successor of a and that constant zero equals the successor of the sum of a and that constant zero, by step one of the successor and fixed numeral addition derivation and step three of the successor and fixed numeral addition derivation

Equation form expr-3ff6171e27f51820

h^(x,y)=μd(β(d,0)=f(x)(i<y)β(d,i+1)=g(x,i,β(d,i)).\hat h(\vec x, y) = \umin{d}{(\beta(d,0) = f(\vec x) \land \bforall{i < y}{\beta(d,i+1) = g(\vec x, i,\beta(d,i)})}.

Read as: h hat of the tuple x and y equals the least d satisfying both of the following conditions. Beta of d and zero equals f of the tuple x. And for every i less than y, beta of d and i plus one equals g of the tuple x, i, and beta of d and i

Means: h hat of the tuple x and y equals the least d satisfying both of the following conditions. Beta of d and zero equals f of the tuple x. And for every i less than y, beta of d and i plus one equals g of the tuple x, i, and beta of d and i

Equation form expr-402bb770441080e5

(d)i+1=g(x,i,(d)i)(d)_{i+1} = g(\vec x, i, (d)_i)

Read as: the entry beta of d and i plus one equals g of the tuple x, i, and the entry beta of d and i

Means: the entry beta of d and i plus one equals g of the tuple x, i, and the entry beta of d and i

Equation form expr-40513eca3baf2791

Af(n0¯,,nk¯,(s)1)A_f(\num{n_0}, \dots, \num{n_k}, (s)_1)

Read as: A subscript f applied to the numerals for n subscript zero through n subscript k, and the entry at position one in the prime power sequence coded by s

Means: A subscript f applied to the numerals for n subscript zero through n subscript k, and the entry at position one in the prime power sequence coded by s

Equation form expr-405fc868048fb039

jnj \geq n

Read as: j is greater than or equal to n

Means: j is greater than or equal to n

Equation form expr-40b384adfe07cde8

χR(n0,,nk)=1\Char{R}(n_0, \dots, n_k) = 1

Read as: the characteristic function of R applied to n subscript zero through n subscript k equals one

Means: the characteristic function of R applied to n subscript zero through n subscript k equals one

Equation form expr-40e658560924b03e

000'' \neq 0'''

Read as: the second successor of zero does not equal the third successor of zero

Means: the second successor of zero does not equal the third successor of zero

Equation form expr-41e97c9c1b01a30b

xA(x)\lexists{x}!A(x)

Read as: the existential formula with bound variable x and matrix A of x

Means: the existential formula with bound variable x and matrix A of x

Equation form expr-4219f3c92eb4e243

m=0m=0

Read as: m equals zero

Means: m equals zero

Equation form expr-428459f7dd087b9a

f(z)f(z)

Read as: f of z

Means: f of z

Equation form expr-43fdb02cd8622dcd

(b+c)=0\eq[(b' + c')][\Obj 0]

Read as: the sum of the successor of b and the successor of c equals the object language constant zero

Means: the sum of the successor of b and the successor of c equals the object language constant zero

Equation form expr-4448ae754d014960

ProvQ(y)\Prov[\Th{Q}](y)

Read as: y is the Goedel number of a sentence provable in Q

Means: y is the Goedel number of a sentence provable in Q

Equation form expr-45098c9492fd6adf

(a+0)=(a+0)\eq[(a' + \Obj 0)][(a + \Obj 0)']

Read as: the sum of the successor of a and the object language constant zero equals the successor of the sum of a and the object language constant zero

Means: the sum of the successor of a and the object language constant zero equals the successor of the sum of a and the object language constant zero

Equation form expr-45b91e8acdd27f18

¬A¬¬B\lnot !A \ident \lnot\lnot !B

Read as: not A is the formula not not B

Means: not A is the formula not not B

Equation form expr-471e29e5dd963354

¬(AB)\lnot(!A \lor !B)

Read as: the negation of the disjunction of A and B

Means: the negation of the disjunction of A and B

Equation form expr-473a7956734d59c6

A(n0,,nk,m)=#Af(n0¯,,nk¯,m¯)#A(n_0, \dots, n_k, m) = \Gn{!A_f(\num{n_0}, \dots, \num{n_k}, \num{m})}

Read as: A of n subscript zero through n subscript k, and m, equals the Goedel number of A subscript f applied to the numerals for n subscript zero through n subscript k, and the numeral for m

Means: A of n subscript zero through n subscript k, and m, equals the Goedel number of A subscript f applied to the numerals for n subscript zero through n subscript k, and the numeral for m

Equation form expr-479a0e6f2fb037ea

g(w,z)0g(w, z) \neq 0

Read as: g of w and z does not equal zero

Means: g of w and z does not equal zero

Equation form expr-47f476387d43584a

zy0modx0zy1modx1zynmodxn.z & \equiv y_0 \mod x_0 \\ z & \equiv y_1 \mod x_1 \\ & \vdots \\ z & \equiv y_n \mod x_n.

Read as: The simultaneous congruences are: z is congruent to y subscript zero modulo x subscript zero; z is congruent to y subscript one modulo x subscript one; and so on, through z congruent to y subscript n modulo x subscript n

Means: The simultaneous congruences are: z is congruent to y subscript zero modulo x subscript zero; z is congruent to y subscript one modulo x subscript one; and so on, through z congruent to y subscript n modulo x subscript n

Equation form expr-487776d8c1feed21

(n¯+m¯)(\num{n} + \num{m})

Read as: the sum of the numeral for n and the numeral for m

Means: the sum of the numeral for n and the numeral for m

Equation form expr-489be0a9ab11e480

Q(n¯+0)=n¯\Th{Q} \Proves \eq[(\num{n} + \Obj 0)][\num{n}]

Read as: Q proves that the sum of the numeral for n and the object language constant zero equals the numeral for n

Means: Q proves that the sum of the numeral for n and the object language constant zero equals the numeral for n

Equation form expr-497d497fc35ba36e

Q1!Q_1

Read as: Q subscript one

Means: Q subscript one

Equation form expr-49f23caa2a921188

Af(n¯,b)!A_f(\num{n}, b)

Read as: A subscript f of the numeral for n and b

Means: A subscript f of the numeral for n and b

Equation form expr-4ad9c626769fce17

A(n0,,nk,m)=Subst(Subst(Subst(#Af#,num(n0),#x0#),),num(nk),#xk#),num(m),#y#)A(n_0, \dots, n_k, m) = \\ \fn{Subst}(\fn{Subst}(\dots\fn{Subst}(\Gn{!A_f}, \fn{num}(n_0), \Gn{x_0}),\\ \dots), \fn{num}(n_k), \Gn{x_k}), \fn{num}(m), \Gn{y})

Read as: A of n subscript zero through n subscript k, and m, equals the result of these nested calls to the substitution coding function Subst. Start with the Goedel number of A subscript f. Substitute the numeral code num of n subscript zero for the variable code of x subscript zero. Continue in order through substitution of num of n subscript k for the variable code of x subscript k. Finally substitute num of m for the variable code of y. Each call takes the current formula code, the replacement numeral code, and the selected variable code, in that order

Means: A of n subscript zero through n subscript k, and m, equals the result of these nested calls to the substitution coding function Subst. Start with the Goedel number of A subscript f. Substitute the numeral code num of n subscript zero for the variable code of x subscript zero. Continue in order through substitution of num of n subscript k for the variable code of x subscript k. Finally substitute num of m for the variable code of y. Each call takes the current formula code, the replacement numeral code, and the selected variable code, in that order

Equation form expr-4ae81572f06e1b88

QQ

Read as: Q

Means: Q

Equation form expr-4c9998b6a2629683

Qn¯=m¯\Th{Q} \Proves \eq[\num n][\num m]

Read as: Q proves that the numeral for n equals the numeral for m

Means: Q proves that the numeral for n equals the numeral for m

Equation form expr-4dc4e01def696af8

Pin\Proj{n}{i}

Read as: the n argument projection function with index i

Means: the n argument projection function with index i

Equation form expr-4e01c892379ba40e

a0,,ana_0,\dots,a_n

Read as: a subscript zero through a subscript n

Means: a subscript zero through a subscript n

Equation form expr-4f0f1e4a3167d257

xix_i

Read as: x subscript i

Means: x subscript i

Equation form expr-4fc68cff6de5c66b

Qt1=n1+1¯\Th{Q} \Proves \eq[t_1'][\num{n_1 + 1}]

Read as: Q proves that the successor of t subscript one equals the numeral for n subscript one plus one

Means: Q proves that the successor of t subscript one equals the numeral for n subscript one plus one

Equation form expr-5081cbc657fe24bd

m¯\num{m}

Read as: the numeral for m

Means: the numeral for m

Equation form expr-50f6f70226bbab06

(n¯+m¯)=y\eq[(\num{n} + \num{m})][y]

Read as: the sum of the numeral for n and the numeral for m equals y

Means: the sum of the numeral for n and the numeral for m equals y

Equation form expr-511e94877bb38a7b

0¯0\num 0 \ident \Obj 0

Read as: the numeral for zero is the object language constant zero

Means: the numeral for zero is the object language constant zero

Equation form expr-5160b22457af7ef4

f(n0,,nk)=(μsR(n0,,nk,s))1.f(n_0,\dots,n_{k}) = (\umin{s}{R(n_0, \dots, n_k, s)})_1.

Read as: f of n subscript zero through n subscript k equals the entry at position one in the prime power sequence whose code is the least s such that R holds of n subscript zero through n subscript k, and s

Means: f of n subscript zero through n subscript k equals the entry at position one in the prime power sequence whose code is the least s such that R holds of n subscript zero through n subscript k, and s

Equation form expr-523e00ddd2c165db

n¯=n¯\eq[\num{n}][\num{n}]

Read as: the numeral for n equals the numeral for n

Means: the numeral for n equals the numeral for n

Equation form expr-5280c8f9e471df51

\ltrue

Read as: truth

Means: truth

Equation form expr-534b34da02a3744c

(b+0)=(a+0)\eq[(b' + \Obj 0)][(a + \Obj 0)]

Read as: the sum of the successor of b and the object language constant zero equals the sum of a and the object language constant zero

Means: the sum of the successor of b and the object language constant zero equals the sum of a and the object language constant zero

Equation form expr-539a22491471bd29

x0,,xnx_0,\dots,x_n

Read as: x subscript zero through x subscript n

Means: x subscript zero through x subscript n

Equation form expr-54e5cc297fef9e74

(A(0)x(A(x)A(x)))xA(x)(!A(\Obj 0) \land \lforall[x][(!A(x) \lif !A(x'))]) \lif \lforall[x][!A(x)]

Read as: If both A holds of the object language constant zero, and for every x, A of x implies A of the successor of x, then A holds of every x

Means: If both A holds of the object language constant zero, and for every x, A of x implies A of the successor of x, then A holds of every x

Equation form expr-55154da3ffef0cbc

Qn¯k¯\Th{Q} \Proves \eq/[\num n][\num k]

Read as: Q proves that the numeral for n does not equal the numeral for k

Means: Q proves that the numeral for n does not equal the numeral for k

Equation form expr-553c7c9c2360e2c5

Ag!A_g

Read as: A subscript g

Means: A subscript g

Equation form expr-5553c013c717e9a8

Q5!Q_5

Read as: Q subscript five

Means: Q subscript five

Equation form expr-55ac8244d52de7d0

iki-k

Read as: i minus k

Means: i minus k

Equation form expr-57953c2c25755935

y(Af(n0¯,,nk¯,y)y=m¯)\lforall[y][(!A_f(\num{n_0}, \dots, \num{n_k}, y) \liff \eq[y][\num{m}])]

Read as: for every y, A subscript f holds of the numerals for n subscript zero through n subscript k, and y, if and only if y equals the numeral for m

Means: for every y, A subscript f holds of the numerals for n subscript zero through n subscript k, and y, if and only if y equals the numeral for m

Equation form expr-57aca383a1921bbe

χ=(n,m)=1\Char{=}(n, m) = 1

Read as: the characteristic function of equality applied to n and m equals one

Means: the characteristic function of equality applied to n and m equals one

Equation form expr-5810ea365f11a260

χR(n0,,nk)=0\Char{R}(n_0, \dots, n_k) = 0

Read as: the characteristic function of R applied to n subscript zero through n subscript k equals zero

Means: the characteristic function of R applied to n subscript zero through n subscript k equals zero

Equation form expr-58c0b6979bc3f4c1

y=x\eq[y][x']

Read as: y equals the successor of x

Means: y equals the successor of x

Equation form expr-58ee3d3914bcad7c

a=0\eq[a][\Obj 0]

Read as: a equals the object language constant zero

Means: a equals the object language constant zero

Equation form expr-594e519ae499312b

zz

Read as: z

Means: z

Equation form expr-59c3bcebf9d9b194

a=0ya=y\eq[a][\Obj 0] \lor \lexists[y][\eq[a][y']]

Read as: either a equals the object language constant zero, or there exists y such that a is the successor of y

Means: either a equals the object language constant zero, or there exists y such that a is the successor of y

Equation form expr-5afa20230f875253

nn \in \Nat

Read as: n is a natural number

Means: n is a natural number

Equation form expr-5b63a60fdb499c3a

N\Struct{N}

Read as: the standard model N

Means: the standard model N

Equation form expr-5bea4caf3b95f01e

f(x0,,xk1)f(x_0,\dots,x_{k-1})

Read as: f of x subscript zero through x subscript k minus one

Means: f of x subscript zero through x subscript k minus one

Equation form expr-5c37345158ceafa2

cc'

Read as: the successor of c

Means: the successor of c

Equation form expr-5d08324acb961fcf

t2t_2

Read as: t subscript two

Means: t subscript two

Equation form expr-5f8d517bbaf86a44

m=f(n)m = f(n)

Read as: m equals f of n

Means: m equals f of n

Equation form expr-5fe6dc6b2281b3d2

zero\Zero

Read as: the zero function

Means: the zero function

Equation form expr-5feceb66ffc86f38

00

Read as: zero

Means: zero

Equation form expr-6009a1b65f58066f

At1=t2!A \ident t_1 = t_2

Read as: A is the formula t subscript one equals t subscript two

Means: A is the formula t subscript one equals t subscript two

Equation form expr-607df55404d282ad

y=xi\eq[y][x_i]

Read as: y equals x subscript i

Means: y equals x subscript i

Equation form expr-613f9747239d288b

(c+b)=n+1¯\eq[(c'+b)'][\num{n+1}']

Read as: the successor of the sum of the successor of c and b equals the successor of the numeral for n plus one

Means: the successor of the sum of the successor of c and b equals the successor of the numeral for n plus one

Equation form expr-61d2d6985fbd6781

Pin(x0,,xn1)=xi\Proj{n}{i}(x_0, \dots, x_{n-1}) = x_i

Read as: the n argument projection function with index i, applied to x subscript zero through x subscript n minus one, equals x subscript i

Means: the n argument projection function with index i, applied to x subscript zero through x subscript n minus one, equals x subscript i

Equation form expr-620d2aa6c7003f41

Ah!A_h

Read as: A subscript h

Means: A subscript h

Equation form expr-62c66a7a5dd70c31

mm

Read as: m

Means: m

Equation form expr-630bea13ff0c157d

(b+a)=0\eq[(b'+a)][\Obj 0']

Read as: the sum of the successor of b and a equals the successor of the object language constant zero

Means: the sum of the successor of b and a equals the successor of the object language constant zero

Equation form expr-63cf3cedc3938049

A=(n¯,m¯,y)!A_=(\num{n}, \num{m}, y)

Read as: A subscript equality applied to the numerals for n and m, and y

Means: A subscript equality applied to the numerals for n and m, and y

Equation form expr-642a159103b087da

0k¯\eq/[0][\num k']

Read as: zero does not equal the successor of the numeral for k

Means: zero does not equal the successor of the numeral for k

Equation form expr-675020bea20828e6

Af,Ag0,,Agk1!A_f, !A_{g_0}, \dots, !A_{g_{k-1}}

Read as: A subscript f, and A subscript g subscript zero through A subscript g subscript k minus one

Means: A subscript f, and A subscript g subscript zero through A subscript g subscript k minus one

Equation form expr-67d70b7414d21313

Qt1<t2\Th{Q} \Proves t_1 < t_2

Read as: Q proves that t subscript one is less than t subscript two

Means: Q proves that t subscript one is less than t subscript two

Equation form expr-67eceadb93cd5af9

ValN(t1)=n1\Value{t_1}{N} = n_1

Read as: the value of t subscript one in the standard model N equals n subscript one

Means: the value of t subscript one in the standard model N equals n subscript one

Equation form expr-686820eb63ee5ceb

add(x0,x1)=x0+x1\Add(x_0, x_1) = x_0+x_1

Read as: the addition function applied to x subscript zero and x subscript one equals the sum of x subscript zero and x subscript one

Means: the addition function applied to x subscript zero and x subscript one equals the sum of x subscript zero and x subscript one

Equation form expr-68f9f7b7f15365cc

AR(n0¯,,nk¯)!A_R(\num{n_0}, \dots, \num{n_k})

Read as: A subscript R applied to the numerals for n subscript zero through n subscript k

Means: A subscript R applied to the numerals for n subscript zero through n subscript k

Equation form expr-6a67af47077a19dd

Qy(Aadd(n¯,m¯,y)y=k¯).\Th{Q} \Proves \lforall[y][(!A_\Add(\num{n}, \num{m}, y) \lif \eq[y][\num{k}])].

Read as: Q proves that for every y, if A subscript Add holds of the numeral for n, the numeral for m, and y, then y equals the numeral for k

Means: Q proves that for every y, if A subscript Add holds of the numeral for n, the numeral for m, and y, then y equals the numeral for k

Equation form expr-6a766438d1de2cc9

n+mn+m

Read as: n plus m

Means: n plus m

Equation form expr-6a85c216edb611d1

QA\Th{Q} \Proves !A

Read as: Q proves that A

Means: Q proves that A

Equation form expr-6aff617426baec7a

a0,,an\tuple{a_0, \dots, a_n}

Read as: the sequence a subscript zero through a subscript n

Means: the sequence a subscript zero through a subscript n

Equation form expr-6b81665d4120803d

Qy(Ah(n¯,y)y=m¯)\Th{Q} \Proves \lforall[y][(!A_h(\num n, y) \lif \eq[y][\num m])]

Read as: Q proves that for every y, if A subscript h holds of the numeral for n and y, then y equals the numeral for m

Means: Q proves that for every y, if A subscript h holds of the numeral for n and y, then y equals the numeral for m

Equation form expr-6b86b273ff34fce1

11

Read as: one

Means: one

Equation form expr-6c5efc1231f47515

z=f(g(x))z = f(g(x))

Read as: z equals f of g of x

Means: z equals f of g of x

Equation form expr-6cd9609ccf118909

n+m¯\num{n+m}'

Read as: the successor of the numeral for n plus m

Means: the successor of the numeral for n plus m

Equation form expr-6d64cdb17c30935b

1+(n+1)d11+(n+1) d_1

Read as: one plus the product of n plus one and d subscript one

Means: one plus the product of n plus one and d subscript one

Equation form expr-6d7097da4387177a

aia_i

Read as: a subscript i

Means: a subscript i

Equation form expr-6e601bf84d5d4eda

AχR(x0,,xk,1¯)!A_{\Char{R}}(x_0, \dots, x_k, \num{1})

Read as: A subscript characteristic function of R, applied to x subscript zero through x subscript k, and the numeral for one

Means: A subscript characteristic function of R, applied to x subscript zero through x subscript k, and the numeral for one

Equation form expr-6ee3034ebd427cec

g(x,z)=0g(x, z) = 0

Read as: g of x and z equals zero

Means: g of x and z equals zero

Equation form expr-6f7ced04d6bee707

¬y(y+a)=0\lnot \lexists[y][\eq[(y'+a)][\Obj 0]]

Read as: there does not exist y such that the sum of the successor of y and a equals the object language constant zero

Means: there does not exist y such that the sum of the successor of y and a equals the object language constant zero

Equation form expr-70514654ed0ce01b

m¯\num{m}'

Read as: the successor of the numeral for m

Means: the successor of the numeral for m

Equation form expr-7199461c674714a8

y=0\eq[y][\Obj 0]

Read as: y equals the object language constant zero

Means: y equals the object language constant zero

Equation form expr-71c45e53665b252d

Qt=n¯\Th{Q} \Proves \eq[t][\num n]

Read as: Q proves that t equals the numeral for n

Means: Q proves that t equals the numeral for n

Equation form expr-722f97d7125f3aac

¬Ag(b,n¯,0)\lnot !A_g(b, \num{n}, \Obj 0)

Read as: not A subscript g of b, the numeral for n, and the object language constant zero

Means: not A subscript g of b, the numeral for n, and the object language constant zero

Equation form expr-72fcd7dafa1f7007

n+1¯\num{n+1}

Read as: the numeral for n plus one

Means: the numeral for n plus one

Equation form expr-72fe42cd2b8d2e97

n¯m¯\eq/[\num{n}][\num{m}]

Read as: the numeral for n does not equal the numeral for m

Means: the numeral for n does not equal the numeral for m

Equation form expr-73353f7ce9a444a4

Af(y0,,yk1,z)!A_f(y_0, \dots, y_{k-1}, z)

Read as: A subscript f applied to y subscript zero through y subscript k minus one, and z

Means: A subscript f applied to y subscript zero through y subscript k minus one, and z

Equation form expr-7338240bcff9771d

k¯\num k'

Read as: the successor of the numeral for k

Means: the successor of the numeral for k

Equation form expr-735c7fab3bc7df2a

Qy((y<m¯m¯<y)y=m¯)and we want to showQy((y<m+1¯m+1¯<y)y=m+1¯)\Th{Q} & \Proves \lforall[y][((y < \num{m} \lor \num{m} < y) \lor \eq[y][\num{m}])] \intertext{and we want to show} \Th{Q} & \Proves \lforall[y][((y < \num{m+1} \lor \num{m+1} < y) \lor \eq[y][\num{m+1}])]

Read as: Assume Q proves: for every y, either y is less than the numeral for m, or the numeral for m is less than y, or y equals the numeral for m. We want to show that Q proves: for every y, either y is less than the numeral for m plus one, or that numeral is less than y, or y equals that numeral

Means: Assume Q proves: for every y, either y is less than the numeral for m, or the numeral for m is less than y, or y equals the numeral for m. We want to show that Q proves: for every y, either y is less than the numeral for m plus one, or that numeral is less than y, or y equals that numeral

Equation form expr-73a9aa343d96822e

(0<aa<0)a=0(\Obj 0 < a \lor a < \Obj 0) \lor \eq[a][\Obj 0]

Read as: either the object language constant zero is less than a, or a is less than that constant, or a equals that constant

Means: either the object language constant zero is less than a, or a is less than that constant, or a equals that constant

Equation form expr-73ad6360c4b0473c

QAf(n0¯,,nk¯,f(n0,,nk)¯)\Th{Q} \Proves !A_f(\num{n_0}, \dots, \num{n_k}, \num{f(n_0, \dots, n_k)})

Read as: Q proves that A subscript f applied to the numerals for n subscript zero through n subscript k, and the numeral for the value of f at n subscript zero through n subscript k

Means: Q proves that A subscript f applied to the numerals for n subscript zero through n subscript k, and the numeral for the value of f at n subscript zero through n subscript k

Equation form expr-7485ac02a69c12f0

QAg(n¯,k¯)since Ag represents g, andQAf(k¯,m¯)since Af represents f. Thus,QAg(n¯,k¯)Af(k¯,m¯)and consequently alsoQy(Ag(n¯,y)Af(y,m¯)),\Th{Q} & \Proves !A_g(\num{n}, \num{k}) \intertext{since $!A_g$ represents~$g$, and} \Th{Q} & \Proves !A_f(\num{k}, \num{m}) \intertext{since $!A_f$ represents~$f$. Thus,} \Th{Q} & \Proves !A_g(\num{n}, \num{k}) \land !A_f(\num{k}, \num{m}) \intertext{and consequently also} \Th{Q} & \Proves \lexists[y][(!A_g(\num{n}, y) \land !A_f(y, \num{m}))],

Read as: Q proves A subscript g of the numeral for n and the numeral for k, since A subscript g represents g. And Q proves A subscript f of the numeral for k and the numeral for m, since A subscript f represents f. Thus Q proves their conjunction. Consequently Q also proves that there exists y such that both A subscript g of the numeral for n and y, and A subscript f of y and the numeral for m

Means: Q proves A subscript g of the numeral for n and the numeral for k, since A subscript g represents g. And Q proves A subscript f of the numeral for k and the numeral for m, since A subscript f represents f. Thus Q proves their conjunction. Consequently Q also proves that there exists y such that both A subscript g of the numeral for n and y, and A subscript f of y and the numeral for m

Equation form expr-74c0e74537bf75aa

xy(x=yx=y)row label Q1x0xrow label Q2x(x=0yx=y)row label Q3x(x+0)=xrow label Q4xy(x+y)=(x+y)row label Q5x(x×0)=0row label Q6xy(x×y)=((x×y)+x)row label Q7xy(x<yz(z+x)=y)row label Q8& \lforall[x][\lforall[y][(\eq[x'][y'] \lif \eq[x][y])]] \tag{$!Q_1$}\\ & \lforall[x][\eq/[\Obj 0][x']] \tag{$!Q_2$}\\ & \lforall[x][(\eq[x][\Obj 0] \lor \lexists[y][\eq[x][y']])] \tag{$!Q_3$}\\ & \lforall[x][\eq[(x + \Obj 0)][x]] \tag{$!Q_4$}\\ & \lforall[x][\lforall[y][\eq[(x + y')][(x + y)']]] \tag{$!Q_5$}\\ & \lforall[x][\eq[(x \times \Obj 0)][\Obj 0]] \tag{$!Q_6$}\\ & \lforall[x][\lforall[y][\eq[(x \times y')][((x \times y) + x)]]] \tag{$!Q_7$}\\ & \lforall[x][\lforall[y][(x < y \liff \lexists[z][\eq[(z' + x)][y]])]] \tag{$!Q_8$}

Read as: Eight axioms for Q. Q subscript one: for all x and y, if the successor of x equals the successor of y, then x equals y. Q subscript two: for every x, the object language constant zero does not equal the successor of x. Q subscript three: for every x, either x equals the object language constant zero, or there exists y such that x equals the successor of y. Q subscript four: for every x, the sum of x and the object language constant zero equals x. Q subscript five: for all x and y, the sum of x and the successor of y equals the successor of the sum of x and y. Q subscript six: for every x, the object language product of x and the constant zero equals that constant zero. Q subscript seven: for all x and y, the object language product of x and the successor of y equals the sum of the object language product of x and y, and x. Q subscript eight: for all x and y, x is less than y if and only if there exists z such that the sum of the successor of z and x equals y. End of the eight axioms.

Means: Eight axioms for Q. Q subscript one: for all x and y, if the successor of x equals the successor of y, then x equals y. Q subscript two: for every x, the object language constant zero does not equal the successor of x. Q subscript three: for every x, either x equals the object language constant zero, or there exists y such that x equals the successor of y. Q subscript four: for every x, the sum of x and the object language constant zero equals x. Q subscript five: for all x and y, the sum of x and the successor of y equals the successor of the sum of x and y. Q subscript six: for every x, the object language product of x and the constant zero equals that constant zero. Q subscript seven: for all x and y, the object language product of x and the successor of y equals the sum of the object language product of x and y, and x. Q subscript eight: for all x and y, x is less than y if and only if there exists z such that the sum of the successor of z and x equals y. End of the eight axioms.

Equation form expr-74e0eb883b673576

zkz_k

Read as: z subscript k

Means: z subscript k

Equation form expr-74f4567a6896230a

=\eq

Read as: the equality symbol

Means: the equality symbol

Equation form expr-74fff1f3fc3ccc0c

m¯+a=m+1¯\eq[\num{m}' + a][\num{m+1}]

Read as: the sum of the successor of the numeral for m and a equals the numeral for m plus one

Means: the sum of the successor of the numeral for m and a equals the numeral for m plus one

Equation form expr-754fcd9ec52e8861

d=J(d0,d1)d = J(d_0,d_1)

Read as: d equals J of d subscript zero and d subscript one

Means: d equals J of d subscript zero and d subscript one

Equation form expr-75ed6f448c24d8db

k=n+mk = n + m

Read as: k equals n plus m

Means: k equals n plus m

Equation form expr-765c65ac668314de

¬Ag(m¯,n¯,0)\lnot !A_g(\num{m}, \num{n}, \Obj 0)

Read as: not A subscript g of the numeral for m, the numeral for n, and the object language constant zero

Means: not A subscript g of the numeral for m, the numeral for n, and the object language constant zero

Equation form expr-76611dd34d50f93b

f(n)=mf(n) = m

Read as: f of n equals m

Means: f of n equals m

Equation form expr-76690a2632c6c282

A(x0,,xk,y)!A(x_0, \dots, x_k, y)

Read as: A applied to x subscript zero through x subscript k, and y

Means: A applied to x subscript zero through x subscript k, and y

Equation form expr-76cbfc0766d6c646

b<m+1¯b' < \num{m+1}

Read as: the successor of b is less than the numeral for m plus one

Means: the successor of b is less than the numeral for m plus one

Equation form expr-7778045033568a46

QAf(n0¯,,nk¯,l¯)\Th{Q} \Proves !A_f(\num{n_0}, \dots, \num{n_k}, \num{l})

Read as: Q proves that A subscript f applied to the numerals for n subscript zero through n subscript k, and the numeral for l

Means: Q proves that A subscript f applied to the numerals for n subscript zero through n subscript k, and the numeral for l

Equation form expr-77ece9c7795ab0b2

z(z+m¯)=b\lexists[z][\eq[(z' + \num{m})][b]]

Read as: there exists z such that the sum of the successor of z and the numeral for m equals b

Means: there exists z such that the sum of the successor of z and the numeral for m equals b

Equation form expr-77f918d83ed74656

n+m¯=y\eq[\num{n+m}][y]

Read as: the numeral for n plus m equals y

Means: the numeral for n plus m equals y

Equation form expr-783819f2e7b1882c

NQ\Sat{N}{\Th{Q}}

Read as: the standard model N satisfies Q

Means: the standard model N satisfies Q

Equation form expr-792de17cc1ae3441

Agi(x0,,xl1,y)!A_{g_i}(x_0, \dots, x_{l-1}, y)

Read as: A subscript g subscript i applied to x subscript zero through x subscript l minus one, and y

Means: A subscript g subscript i applied to x subscript zero through x subscript l minus one, and y

Equation form expr-7a5bbe0fc2709653

(c+m¯)=b\eq[(c' + \num{m})][b]

Read as: the sum of the successor of c and the numeral for m equals b

Means: the sum of the successor of c and the numeral for m equals b

Equation form expr-7b8ba390a71f512b

zero(x)=0\Zero(x) = 0

Read as: the zero function applied to x equals zero

Means: the zero function applied to x equals zero

Equation form expr-7d282b412739ae71

(a<00<a)a=0(a < \Obj 0 \lor \Obj 0 < a) \lor \eq[a][\Obj 0]

Read as: either a is less than the object language constant zero, or that constant is less than a, or a equals that constant

Means: either a is less than the object language constant zero, or that constant is less than a, or a equals that constant

Equation form expr-7d5aa605dde1dd9d

QA(0¯)A(k1¯)\Th{Q} \Proves !A(\num 0) \land \dots \land !A(\num{k-1})

Read as: Q proves that the finite conjunction of A applied to each numeral from zero through k minus one

Means: Q proves that the finite conjunction of A applied to each numeral from zero through k minus one

Equation form expr-7d7a67425bb66671

TA\Proves !T \lif !A

Read as: the implication from T to A is provable with no nonlogical premises

Means: the implication from T to A is provable with no nonlogical premises

Equation form expr-7d7eadee71a7e564

m+1m+1

Read as: m plus one

Means: m plus one

Equation form expr-7dd2e78c28fc35bf

m=k+1m = k+1

Read as: m equals k plus one

Means: m equals k plus one

Equation form expr-7e2770a26fc50a59

w<xw < x

Read as: w is less than x

Means: w is less than x

Equation form expr-7f024b2d7f1db4d4

n¯\num{n}

Read as: the numeral for n

Means: the numeral for n

Equation form expr-801318c363bd13ba

b<m¯b < \num{m}

Read as: b is less than the numeral for m

Means: b is less than the numeral for m

Equation form expr-8022b4c1dd18ddb5

ValN(t1)ValN(t2)\Value{t_1}{N} \neq \Value{t_2}{N}

Read as: the value of t subscript one in the standard model N does not equal the value of t subscript two in the standard model N

Means: the value of t subscript one in the standard model N does not equal the value of t subscript two in the standard model N

Equation form expr-8071422cd3693781

Q(x<t)A(x)\Th{Q} \Proves \bexists{x<t}{!A(x)}

Read as: Q proves that there exists x less than t such that A of x

Means: Q proves that there exists x less than t such that A of x

Equation form expr-80b17a5f996cbf72

Af(x0,,xk,y)!A_f(x_0,\dots,x_k,y)

Read as: A subscript f applied to x subscript zero through x subscript k, and y

Means: A subscript f applied to x subscript zero through x subscript k, and y

Equation form expr-80fce15b99d444a5

Qn¯m¯\Th{Q} \Proves \eq/[\num{n}][\num{m}]

Read as: Q proves that the numeral for n does not equal the numeral for m

Means: Q proves that the numeral for n does not equal the numeral for m

Equation form expr-81aa5a490db29cc9

A(x)!A(x)

Read as: A of x

Means: A of x

Equation form expr-8238c028f61fc0f7

A!A

Read as: A

Means: A

Equation form expr-8254c329a92850f6

kk

Read as: k

Means: k

Equation form expr-8288accffcbf319e

g(m,n)=0g(m, n) = 0

Read as: g of m and n equals zero

Means: g of m and n equals zero

Equation form expr-83c29a4e8dc685fc

1+(i+1)m1 + (i+1)m

Read as: one plus the product of i plus one and m

Means: one plus the product of i plus one and m

Equation form expr-83ffd5dcb893e03c

(c+b)=(c+b)\eq[(c' + b)'][(c' + b')]

Read as: the successor of the sum of the successor of c and b equals the sum of the successor of c and the successor of b

Means: the successor of the sum of the successor of c and b equals the sum of the successor of c and the successor of b

Equation form expr-841c7796b253f8c4

χ=(n,m)=0\Char=(n, m) = 0

Read as: the characteristic function of equality applied to n and m equals zero

Means: the characteristic function of equality applied to n and m equals zero

Equation form expr-84c4519d1afda28e

Q(n¯+m+1¯)=n+m+1¯\Th{Q} \Proves \eq[(\num{n} + \num{m+1})][\num{n+m+1}]

Read as: Q proves that the sum of the numeral for n and the numeral for m plus one equals the numeral for n plus m plus one

Means: Q proves that the sum of the numeral for n and the numeral for m plus one equals the numeral for n plus m plus one

Equation form expr-866007381d5c48a8

d1d_1

Read as: d subscript one

Means: d subscript one

Equation form expr-86bc40a9dfa0a3bf

d0d_0

Read as: d subscript zero

Means: d subscript zero

Equation form expr-86c174ef8f52728a

QyBT(e¯,n¯,y)\Th{Q} \Proves/ \lexists[y][!B_T(\num{e}, \num{n}, y)]

Read as: Q does not prove that there exists y such that B subscript T holds of the numeral for e, the numeral for n, and y

Means: Q does not prove that there exists y such that B subscript T holds of the numeral for e, the numeral for n, and y

Equation form expr-86d0ea318fb5f9be

R(n0,,nk,s)iffPrfQ((s)0,A(n0,,nk,(s)1))R(n_0, \dots, n_k, s) \quad\text{iff}\quad \Prf[\Th{Q}]((s)_0, A(n_0, \dots, n_k, (s)_1))

Read as: R holds of n subscript zero through n subscript k, and s, if and only if the entry at position zero in the prime power sequence coded by s is a derivation code in Q for the formula with code A of n subscript zero through n subscript k, and the entry at position one in that sequence

Means: R holds of n subscript zero through n subscript k, and s, if and only if the entry at position zero in the prime power sequence coded by s is a derivation code in Q for the formula with code A of n subscript zero through n subscript k, and the entry at position one in that sequence

Equation form expr-8779068734acaece

·\cdot

Read as: the numerical multiplication operation

Means: the numerical multiplication operation

Equation form expr-87cc3fc5bd5779da

Qt2=m¯\Th{Q} \Proves \eq[t_2][\num m]

Read as: Q proves that t subscript two equals the numeral for m

Means: Q proves that t subscript two equals the numeral for m

Equation form expr-88a51162b7219690

(s)0(s)_0

Read as: the entry at position zero in the prime power sequence coded by s

Means: the entry at position zero in the prime power sequence coded by s

Equation form expr-893489f0e6d4eb45

Nt1<t2\Sat{N}{t_1 < t_2}

Read as: in the standard model N, t subscript one is less than t subscript two

Means: in the standard model N, t subscript one is less than t subscript two

Equation form expr-8a08932817a94ba5

b<n+1¯b < \num{n+1}

Read as: b is less than the numeral for n plus one

Means: b is less than the numeral for n plus one

Equation form expr-8a15984a78d67748

ValN(t1)=ValN(t2)\Value{t_1}{N} = \Value{t_2}{N}

Read as: the value of t subscript one in the standard model N equals the value of t subscript two in the standard model N

Means: the value of t subscript one in the standard model N equals the value of t subscript two in the standard model N

Equation form expr-8a4fc85668fc8882

pxkp \mid x_k

Read as: p divides x subscript k

Means: p divides x subscript k

Equation form expr-8ab9ee2cb0c96a7a

(b+0)=0\eq[(b' + \Obj 0)][\Obj 0]

Read as: the sum of the successor of b and the object language constant zero equals the object language constant zero

Means: the sum of the successor of b and the object language constant zero equals the object language constant zero

Equation form expr-8abffd0e59bff9dd

AR(n0¯,,nk¯)!A_R(\num{n_0},\dots,\num{n_k})

Read as: A subscript R applied to the numerals for n subscript zero through n subscript k

Means: A subscript R applied to the numerals for n subscript zero through n subscript k

Equation form expr-8b2aa30dd4cbfbef

pmp \mid m

Read as: p divides m

Means: p divides m

Equation form expr-8b6c08b49f493c4b

x(x<tA(x))\lforall[x][(x < t \lif !A(x))]

Read as: for every x, if x is less than t then A of x

Means: for every x, if x is less than t then A of x

Equation form expr-8b99f1e835f81e5d

Ag(b,n¯,0)!A_g(b, \num{n}, \Obj 0)

Read as: A subscript g of b, the numeral for n, and the object language constant zero

Means: A subscript g of b, the numeral for n, and the object language constant zero

Equation form expr-8ba33efa103d1d43

Af(z,y)!A_f(z, y)

Read as: A subscript f of z and y

Means: A subscript f of z and y

Equation form expr-8c2574892063f995

RR

Read as: R

Means: R

Equation form expr-8c531a72c7fe2655

m=0m = 0

Read as: m equals zero

Means: m equals zero

Equation form expr-8c76422868ff432e

b=0\eq[b'][\Obj 0]

Read as: the successor of b equals the object language constant zero

Means: the successor of b equals the object language constant zero

Equation form expr-8e30179df74cc60a

Q8!Q_8

Read as: Q subscript eight

Means: Q subscript eight

Equation form expr-8e6aea830823dc37

Qt2=n¯2\Th{Q} \Proves \eq[t_2][\num n_2]

Read as: Q proves that t subscript two equals the numeral for n subscript two

Means: Q proves that t subscript two equals the numeral for n subscript two

Equation form expr-8ef7d16bdf52cb52

(c+b)=n+1¯\eq[(c'+b')][\num{n+1}']

Read as: the sum of the successor of c and the successor of b equals the successor of the numeral for n plus one

Means: the sum of the successor of c and the successor of b equals the successor of the numeral for n plus one

Equation form expr-91b4c578b18b4766

a<m+1¯a < \num{m+1}

Read as: a is less than the numeral for m plus one

Means: a is less than the numeral for m plus one

Equation form expr-930ba382516e4117

m=nm = n

Read as: m equals n

Means: m equals n

Equation form expr-9332333c95b92b1a

Qt1=n¯1\Th{Q} \Proves \eq[t_1'][{\num n_1}']

Read as: Q proves that the successor of t subscript one equals the successor of the numeral for n subscript one

Means: Q proves that the successor of t subscript one equals the successor of the numeral for n subscript one

Equation form expr-93d82ea1ce9d4511

x=0¯x=k¯x = \num 0 \lor \dots \lor x = \num k

Read as: x equals one of the numerals from zero through k

Means: x equals one of the numerals from zero through k

Equation form expr-94505e429fe1baae

m¯<b\num{m} < b

Read as: the numeral for m is less than b

Means: the numeral for m is less than b

Equation form expr-94c266908603cc20

(b+0)=b\eq[(b' + \Obj 0)][b']

Read as: the sum of the successor of b and the object language constant zero equals the successor of b

Means: the sum of the successor of b and the object language constant zero equals the successor of b

Equation form expr-94d55460ef707d5e

(a+0)=a\eq[(a + \Obj 0)][a]

Read as: the sum of a and the object language constant zero equals a

Means: the sum of a and the object language constant zero equals a

Equation form expr-94ebc8441ce25a95

n<ValN(t)n < \Value{t}{N}

Read as: n is less than the value of t in the standard model N

Means: n is less than the value of t in the standard model N

Equation form expr-9521e1b505384499

AR(x0,,xk)!A_R(x_0,\dots,x_k)

Read as: A subscript R applied to x subscript zero through x subscript k

Means: A subscript R applied to x subscript zero through x subscript k

Equation form expr-968e772cf168b7f1

x,yx,y

Read as: x and y

Means: x and y

Equation form expr-970988c031322f17

Q(n¯+m¯)=n+m¯\Th{Q} \Proves \eq[(\num{n} + \num{m})][\num{n+m}]

Read as: Q proves that the sum of the numeral for n and the numeral for m equals the numeral for n plus m

Means: Q proves that the sum of the numeral for n and the numeral for m equals the numeral for n plus m

Equation form expr-9739d6e0c9f5971c

xB(x)\lexists[x][!B(x)]

Read as: there exists x such that B of x

Means: there exists x such that B of x

Equation form expr-976c5f41c4507aea

Q(n¯+m¯)=(n¯+m¯)\Th{Q} \Proves \eq[(\num{n} + \num{m}')][(\num{n}+\num{m})']

Read as: Q proves that the sum of the numeral for n and the successor of the numeral for m equals the successor of the sum of the numeral for n and the numeral for m

Means: Q proves that the sum of the numeral for n and the successor of the numeral for m equals the successor of the sum of the numeral for n and the numeral for m

Equation form expr-97785cf468546005

¬(AB)\lnot (!A \land !B)

Read as: the negation of the conjunction of A and B

Means: the negation of the conjunction of A and B

Equation form expr-97e8e4bcf0e37115

Qn¯+k¯=m¯\Th{Q} \Proves \eq[\num n + {\num k}'][\num m]

Read as: Q proves that the sum of the numeral for n and the successor of the numeral for k equals the numeral for m

Means: Q proves that the sum of the numeral for n and the successor of the numeral for k equals the numeral for m

Equation form expr-97ea19d02577e8a3

Af(n0¯,,nk¯,m¯)!A_f(\num{n_0}, \dots, \num{n_k}, \num{m})

Read as: A subscript f applied to the numerals for n subscript zero through n subscript k, and the numeral for m

Means: A subscript f applied to the numerals for n subscript zero through n subscript k, and the numeral for m

Equation form expr-9829f2e34e8f0b11

1¯\num{1}

Read as: the numeral for one

Means: the numeral for one

Equation form expr-984fa2e59cd0d0c7

ValN((t1))=n1+1\Value{(t_1')}{N} = n_1 + 1

Read as: the value of the successor of t subscript one in the standard model N equals n subscript one plus one

Means: the value of the successor of t subscript one in the standard model N equals n subscript one plus one

Equation form expr-9863b00bde618db4

(x<k+1¯)A(x)\bforall{x<\num{k+1}}{!A(x)}

Read as: for every x less than the numeral for k plus one, A of x

Means: for every x less than the numeral for k plus one, A of x

Equation form expr-9872759fd3b4ac8d

a=m+1¯\eq[a][\num{m+1}]

Read as: a equals the numeral for m plus one

Means: a equals the numeral for m plus one

Equation form expr-98f0455530b5b3d8

gk1g_{k-1}

Read as: g subscript k minus one

Means: g subscript k minus one

Equation form expr-9936aa9b7ddc35fc

y(Af(n0¯,,nk¯,y)l¯=y)\lforall[y][(!A_f(\num{n_0}, \dots, \num{n_k}, y) \lif \num{l} = y)]

Read as: for every y, if A subscript f holds of the numerals for n subscript zero through n subscript k, and y, then the numeral for l equals y

Means: for every y, if A subscript f holds of the numerals for n subscript zero through n subscript k, and y, then the numeral for l equals y

Equation form expr-99530d605f8f40ba

(n¯m¯0=0)(\eq/[\num{n}][\num{m}] \land \Obj 0 = \Obj 0)

Read as: both the numeral for n does not equal the numeral for m, and the object language constant zero equals itself

Means: both the numeral for n does not equal the numeral for m, and the object language constant zero equals itself

Equation form expr-997b5f48ec78691e

Qn¯m¯Q \Proves \eq/[\num n][\num m]

Read as: Q proves that the numeral for n does not equal the numeral for m

Means: Q proves that the numeral for n does not equal the numeral for m

Equation form expr-99c79ec8f502f506

h(x,z)h(x,\vec z)

Read as: h of x and the tuple z

Means: h of x and the tuple z

Equation form expr-99cd0a95829c8be4

QA(n¯)\Th{Q} \Proves !A(\num n)

Read as: Q proves that A of the numeral for n

Means: Q proves that A of the numeral for n

Equation form expr-99deeccf026a5fbb

c(ab)c \mid (a-b)

Read as: c divides the difference a minus b

Means: c divides the difference a minus b

Equation form expr-99eaba70cc483016

(c+b)=m¯\eq[(c' + b)][\num{m}]

Read as: the sum of the successor of c and b equals the numeral for m

Means: the sum of the successor of c and b equals the numeral for m

Equation form expr-9a1bfbe943988e5d

z(z+0)=a\lexists[z][\eq[(z' + \Obj 0)][a]]

Read as: there exists z such that the sum of the successor of z and the object language constant zero equals a

Means: there exists z such that the sum of the successor of z and the object language constant zero equals a

Equation form expr-9a60b2b0354496bd

Af(x0,,xk1,y)!A_f(x_0,\dots,x_{k-1},y)

Read as: A subscript f applied to x subscript zero through x subscript k minus one, and y

Means: A subscript f applied to x subscript zero through x subscript k minus one, and y

Equation form expr-9ae03202d8082a50

p1+(k+1)mp \mid 1 + (k+1) m

Read as: p divides one plus the product of k plus one and m

Means: p divides one plus the product of k plus one and m

Equation form expr-9b1130dee3faf818

Σ1\Sigma_1

Read as: Sigma one

Means: Sigma one

Equation form expr-9b306121bac7d91c

a<n+2¯a < \num {n+2}

Read as: a is less than the numeral for n plus two

Means: a is less than the numeral for n plus two

Equation form expr-9b7ba6bb774a5ef4

0\Obj{0}''

Read as: the second successor of the object language constant zero

Means: the second successor of the object language constant zero

Equation form expr-9ba6ff8b57246881

φe(n)\cfind{e}(n) \fdefined

Read as: the partial computable function with index e is defined at n

Means: the partial computable function with index e is defined at n

Equation form expr-9c24810c7efa7b9d

y0yk1(Ag0(x0,,xl1,y0)Agk1(x0,,xl1,yk1)Af(y0,,yk1,z))\lexists[y_0\dots][\lexists[y_{k-1}][(!A_{g_0}(x_0,\dots,x_{l-1},y_0) \land \dots \land {}]]\\ !A_{g_{k-1}}(x_0,\dots,x_{l-1},y_{k-1}) \land !A_f(y_0,\dots,y_{k-1},z))

Read as: There exist y subscript zero through y subscript k minus one such that all of the following hold. A subscript g subscript zero holds of x subscript zero through x subscript l minus one, and y subscript zero. Continue this conjunction through A subscript g subscript k minus one, applied to the same input tuple and y subscript k minus one. Finally A subscript f holds of y subscript zero through y subscript k minus one, and z

Means: There exist y subscript zero through y subscript k minus one such that all of the following hold. A subscript g subscript zero holds of x subscript zero through x subscript l minus one, and y subscript zero. Continue this conjunction through A subscript g subscript k minus one, applied to the same input tuple and y subscript k minus one. Finally A subscript f holds of y subscript zero through y subscript k minus one, and z

Equation form expr-9c407114b462de60

g(e,n)g(e, n)

Read as: g of e and n

Means: g of e and n

Equation form expr-9d0c6534a53aea21

ValN(t)=0\Value{t}{N} = 0

Read as: the value of t in the standard model N equals zero

Means: the value of t in the standard model N equals zero

Equation form expr-9d93aac1dee956be

Qy(y=0zy=z)\Th{Q} \Proves \lforall[y][(\eq[y][\Obj 0] \lor \lexists[z][\eq[y][z']])]

Read as: Q proves that for every y, either y equals the object language constant zero, or there exists z such that y is the successor of z

Means: Q proves that for every y, either y equals the object language constant zero, or there exists z such that y is the successor of z

Equation form expr-9ee230f22d8cf57f

xyx \mid y

Read as: x divides y

Means: x divides y

Equation form expr-9f13c5dc7a2b3efe

x0x\lforall[x][\eq/[0][x']]

Read as: for every x, zero is not equal to the successor of x

Means: for every x, zero is not equal to the successor of x

Equation form expr-9f3504db545ac1c7

Q3!Q_3

Read as: Q subscript three

Means: Q subscript three

Equation form expr-9f95de631c898c08

(c+m¯)=b\eq[(c' + \num{m})'][b']

Read as: the successor of the sum of the successor of c and the numeral for m equals the successor of b

Means: the successor of the sum of the successor of c and the numeral for m equals the successor of b

Equation form expr-9fb0570ccfbbd6a2

Qy(A=(n¯,m¯,y)y=1¯)\Th{Q} \Proves \lforall[y][(!A_=(\num{n}, \num{m}, y) \lif \eq[y][\num{1}])]

Read as: Q proves that for every y, if A subscript equality holds of the numeral for n, the numeral for m, and y, then y equals the numeral for one

Means: Q proves that for every y, if A subscript equality holds of the numeral for n, the numeral for m, and y, then y equals the numeral for one

Equation form expr-9ff21a3a6c7fede3

y((A(0)x(A(x)A(x)))xA(x))\lforall[y][((!A(\Obj 0) \land \lforall[x][(!A(x) \lif !A(x'))]) \lif \lforall[x][!A(x)])]

Read as: For every y: if both A holds of the object language constant zero, and for every x, A of x implies A of the successor of x, then A holds of every x. The occurrences of y as an additional parameter of A are suppressed in the displayed notation

Means: For every y: if both A holds of the object language constant zero, and for every x, A of x implies A of the successor of x, then A holds of every x. The occurrences of y as an additional parameter of A are suppressed in the displayed notation

Equation form expr-9ff870ac21c87903

yi<xiy_i < x_i

Read as: y subscript i is less than x subscript i

Means: y subscript i is less than x subscript i

Equation form expr-a0d5d7ad8b7c5f0f

Q0=0¯\Th{Q} \Proves \eq[\Obj 0][\num 0]

Read as: Q proves that the object language constant zero equals the numeral for zero

Means: Q proves that the object language constant zero equals the numeral for zero

Equation form expr-a0f1d688b8d2c454

Q¬(AB)\Th{Q} \Proves \lnot (!A \land !B)

Read as: Q proves that not both A and B

Means: Q proves that not both A and B

Equation form expr-a13fad715d3d8f39

f(x0,,xk)f(x_0, \dots, x_k)

Read as: f of x subscript zero through x subscript k

Means: f of x subscript zero through x subscript k

Equation form expr-a180d671401aa95a

R(n0,,nk)R(n_0, \dots, n_k)

Read as: R of n subscript zero through n subscript k

Means: R of n subscript zero through n subscript k

Equation form expr-a1fce4363854ff88

yy

Read as: y

Means: y

Equation form expr-a2277e0b98ac28a5

g(x)g(x)

Read as: g of x

Means: g of x

Equation form expr-a271a4166cc5926a

¬(x<t)A(x)\lnot \bforall{x<t}{!A(x)}

Read as: the negation of the bounded universal formula with variable x, bound t, and matrix A of x

Means: the negation of the bounded universal formula with variable x, bound t, and matrix A of x

Equation form expr-a2930a4518e17ed7

y=0y = \Obj 0

Read as: y equals the object language constant zero

Means: y equals the object language constant zero

Equation form expr-a31439ad6799912e

Q2!Q_2

Read as: Q subscript two

Means: Q subscript two

Equation form expr-a318c24216defe20

++

Read as: plus

Means: plus

Equation form expr-a3466b8f618426a2

T\Th{T}

Read as: T

Means: T

Equation form expr-a37cb0fe7345926a

y=0¯\eq[y][\num{0}]

Read as: y equals the numeral for zero

Means: y equals the numeral for zero

Equation form expr-a3a5c1aaeb0c0304

y=(x0+x1)\eq[y][(x_0 + x_1)]

Read as: y equals the sum of x subscript zero and x subscript one

Means: y equals the sum of x subscript zero and x subscript one

Equation form expr-a3a795ab86ae620b

z+n¯=m¯\eq[z' + \num n][\num m]

Read as: the sum of the successor of z and the numeral for n equals the numeral for m

Means: the sum of the successor of z and the numeral for n equals the numeral for m

Equation form expr-a4cd1fc4fcb08699

xxx\lforall[x][\eq/[x][x']]

Read as: for every x, x is not equal to its successor

Means: for every x, x is not equal to its successor

Equation form expr-a5b928f808bc85b6

QAg(m¯,n¯,0)w(w<m¯¬Ag(w,n¯,0)).Since Ag(x,z,y) represents g(x,z) and g(m,n)=0 if f(n)=m, we haveQAg(m¯,n¯,0).If f(n)=m, then for every k<m, g(k,n)0. SoQ¬Ag(k¯,n¯,0).We get thatQw(w<m¯¬Ag(w,n¯,0)).\Th{Q} & \Proves !A_g(\num{m}, \num{n}, \Obj 0) \land \lforall[w][(w < \num{m} \lif \lnot !A_g(w, \num{n}, \Obj 0))]. \notag \intertext{Since $!A_g(x, z, y)$ represents $g(x, z)$ and $g(m, n) = 0$ if $f(n) = m$, we have} \Th{Q} & \Proves !A_g(\num{m}, \num{n}, \Obj 0). \notag \intertext{If $f(n) = m$, then for every $k < m$, $g(k, n) \neq 0$. So} \Th{Q} & \Proves \lnot !A_g(\num{k}, \num{n}, \Obj 0). \notag \intertext{We get that} \Th{Q} & \Proves \lforall[w][(w < \num{m} \lif \lnot !A_g(w, \num{n}, \Obj 0))]. \ollabel{rep-less}

Read as: We seek a proof in Q of the conjunction of A subscript g of the numeral for m, the numeral for n, and the object language constant zero, with the statement that every w less than the numeral for m fails to satisfy A subscript g of w, the numeral for n, and that constant zero. Since A subscript g of x, z, and y represents g of x and z, and g of m and n equals zero if f of n equals m, Q proves the first conjunct. If f of n equals m, then for every k less than m, g of k and n is not zero. So Q proves not A subscript g of the numeral for k, the numeral for n, and that constant zero. We obtain the final displayed claim: Q proves that for every w, if w is less than the numeral for m then not A subscript g of w, the numeral for n, and that constant zero

Means: We seek a proof in Q of the conjunction of A subscript g of the numeral for m, the numeral for n, and the object language constant zero, with the statement that every w less than the numeral for m fails to satisfy A subscript g of w, the numeral for n, and that constant zero. Since A subscript g of x, z, and y represents g of x and z, and g of m and n equals zero if f of n equals m, Q proves the first conjunct. If f of n equals m, then for every k less than m, g of k and n is not zero. So Q proves not A subscript g of the numeral for k, the numeral for n, and that constant zero. We obtain the final displayed claim: Q proves that for every w, if w is less than the numeral for m then not A subscript g of w, the numeral for n, and that constant zero

Equation form expr-a67fdb34453f737a

y(y+a)=0\lexists[y][\eq[(y'+a)][\Obj 0']]

Read as: there exists y such that the sum of the successor of y and a equals the successor of the object language constant zero

Means: there exists y such that the sum of the successor of y and a equals the successor of the object language constant zero

Equation form expr-a6c0b99522e3fba2

(b+c)=0\eq[(b' + c)][\Obj 0]

Read as: the sum of the successor of b and c equals the object language constant zero

Means: the sum of the successor of b and c equals the object language constant zero

Equation form expr-a726dcd1f0fd3123

T(e,n,s)T(e, n, s)

Read as: Kleene T of e, n, and s

Means: Kleene T of e, n, and s

Equation form expr-a7799faa3faed46b

QB\Th{Q} \Proves !B

Read as: Q proves that B

Means: Q proves that B

Equation form expr-a92a1a72f6d79dff

x0=1+mx1=1+2·mx2=1+3·mxn=1+(n+1)·mx_0 & = 1 + m \\ x_1 & = 1 + 2 \cdot m \\ x_2 & = 1 + 3 \cdot m \\ & \vdots \\ x_n & = 1 + (n+1) \cdot m

Read as: x subscript zero equals one plus m. x subscript one equals one plus two times m. x subscript two equals one plus three times m. Continue in this pattern through x subscript n, which equals one plus the product of n plus one and m

Means: x subscript zero equals one plus m. x subscript one equals one plus two times m. x subscript two equals one plus three times m. Continue in this pattern through x subscript n, which equals one plus the product of n plus one and m

Equation form expr-a9ac716b2b2b6374

b=m¯\eq[b'][\num{m}']

Read as: the successor of b equals the successor of the numeral for m

Means: the successor of b equals the successor of the numeral for m

Equation form expr-a9d343fbfceb6cbf

(b<m¯m¯<b)b=m¯(b < \num{m} \lor \num{m} < b) \lor \eq[b][\num{m}]

Read as: either b is less than the numeral for m, or the numeral for m is less than b, or b equals the numeral for m

Means: either b is less than the numeral for m, or the numeral for m is less than b, or b equals the numeral for m

Equation form expr-aa311401800bb784

Qn1¯+n2¯=n1+n2¯\Th{Q} \Proves \eq[\num{n_1} + \num{n_2}][\num{n_1 + n_2}]

Read as: Q proves that the sum of the numeral for n subscript one and the numeral for n subscript two equals the numeral for n subscript one plus n subscript two

Means: Q proves that the sum of the numeral for n subscript one and the numeral for n subscript two equals the numeral for n subscript one plus n subscript two

Equation form expr-aa3501e31cd10004

a=1¯a=n+1¯\eq[a][\num{1}] \lor \dots \lor \eq[a][\num{n+1}]

Read as: a equals one of the numerals from one through n plus one

Means: a equals one of the numerals from one through n plus one

Equation form expr-aaa9402664f1a41f

hh

Read as: h

Means: h

Equation form expr-ab0b4ea97abfc843

Qt1+t2=n1¯+n2¯\Th{Q} \Proves \eq[t_1 + t_2][\num{n_1} + \num{n_2}]

Read as: Q proves that the sum of t subscript one and t subscript two equals the sum of the numeral for n subscript one and the numeral for n subscript two

Means: Q proves that the sum of t subscript one and t subscript two equals the sum of the numeral for n subscript one and the numeral for n subscript two

Equation form expr-acc4a828c3018e3e

a=0a=n+1¯\eq[a][\Obj 0] \lor \dots \lor \eq[a][\num{n+1}]

Read as: a equals one of the numerals from zero through n plus one

Means: a equals one of the numerals from zero through n plus one

Equation form expr-ad82ed0b26185a19

Q¬(AB)\Th{Q} \Proves \lnot(!A \lor !B)

Read as: Q proves that not the disjunction of A and B

Means: Q proves that not the disjunction of A and B

Equation form expr-ad988faab4472ea6

y0,,yn\tuple{y_0, \dots,y_n}

Read as: the sequence y subscript zero through y subscript n

Means: the sequence y subscript zero through y subscript n

Equation form expr-adedc2ab1c653ff0

n¯\num{n}'

Read as: the successor of the numeral for n

Means: the successor of the numeral for n

Equation form expr-aeba77fc8715af8d

Qt1=n¯\Th{Q} \Proves \eq[t_1][\num n]

Read as: Q proves that t subscript one equals the numeral for n

Means: Q proves that t subscript one equals the numeral for n

Equation form expr-af29e8d040e75ef3

num\fn{num}

Read as: the numeral coding function num

Means: the numeral coding function num

Equation form expr-b030cfb307e9692e

m=ValN(t2)m = \Value{t_2}{N}

Read as: m equals the value of t subscript two in the standard model N

Means: m equals the value of t subscript two in the standard model N

Equation form expr-b06799d3205fa44d

Δ0\Delta_0

Read as: Delta zero

Means: Delta zero

Equation form expr-b2ce9cd8bef51e4c

AxB(x)!A \ident \lforall[x][!B(x)]

Read as: A is the formula for every x, B of x

Means: A is the formula for every x, B of x

Equation form expr-b2daad0d82bb1fc2

d0aimod(1+(i+1)d1)d_0 \equiv a_i \mod (1+(i+1)d_1)

Read as: d subscript zero is congruent to a subscript i modulo one plus the product of i plus one and d subscript one

Means: d subscript zero is congruent to a subscript i modulo one plus the product of i plus one and d subscript one

Equation form expr-b3f6ba5bad3f6071

n0n_0

Read as: n subscript zero

Means: n subscript zero

Equation form expr-b4e6bdbd4df9905c

Q(AB)\Th{Q} \Proves (!A \land !B)

Read as: Q proves that both A and B

Means: Q proves that both A and B

Equation form expr-b5348603f9f5b166

Nt1<t2\Sat/{N}{t_1 < t_2}

Read as: the standard model N does not satisfy that t subscript one is less than t subscript two

Means: the standard model N does not satisfy that t subscript one is less than t subscript two

Equation form expr-b53fe84dcdb8d4ca

m=k+1m = k + 1

Read as: m equals k plus one

Means: m equals k plus one

Equation form expr-b620f7fd0a05aeb7

0¯\num{0}

Read as: the numeral for zero

Means: the numeral for zero

Equation form expr-b70c52a65a4a70fb

Qt1=t2\Th{Q} \Proves \eq[t_1][t_2]

Read as: Q proves that t subscript one equals t subscript two

Means: Q proves that t subscript one equals t subscript two

Equation form expr-b70e215b9e4d1e68

m¯m+1¯\num{m}' \ident \num{m+1}

Read as: the successor of the numeral for m is the numeral for m plus one

Means: the successor of the numeral for m is the numeral for m plus one

Equation form expr-b77b10aec6f1a7d2

ai=rem(1+(i+1)d1,d0).a_i = \fn{rem}(1+(i+1)d_1,d_0).

Read as: a subscript i equals the remainder when d subscript zero is divided by one plus the product of i plus one and d subscript one

Means: a subscript i equals the remainder when d subscript zero is divided by one plus the product of i plus one and d subscript one

Equation form expr-b9711ee2915de9c0

add\Add

Read as: the addition function

Means: the addition function

Equation form expr-ba57289fd17703bd

mf(n0,,nk)m \neq f(n_0, \dots, n_k)

Read as: m does not equal f of n subscript zero through n subscript k

Means: m does not equal f of n subscript zero through n subscript k

Equation form expr-ba6d58a2fdaae197

Q(x<k+1¯)A(x)\Th{Q} \Proves \bforall{x<\num{k+1}}{!A(x)}

Read as: Q proves that for every x less than the numeral for k plus one, A of x

Means: Q proves that for every x less than the numeral for k plus one, A of x

Equation form expr-ba7f9ad8e3be5eab

Q(a+n¯)=(a+n¯)by axiom Q5Q(a+n¯)=(a+n¯)inductive hypothesisQ(a+n¯)=(a+n¯)by step five of the successor and fixed numeral addition derivation and step six of the successor and fixed numeral addition derivation.\Th{Q} & \Proves \eq[(a' + \num n')][(a' + \num n)'] \quad \text{by axiom $!Q_5$} \ollabel{step5}\\ \Th{Q} & \Proves \eq[(a' + \num n')][(a + \num n')'] \quad \text{inductive hypothesis} \ollabel{step6}\\ \Th{Q} & \Proves \eq[(a' + \num n)'][(a + \num n')'] \quad \text{by \olref{step5} and \olref{step6}.} \notag

Read as: Step five. Q proves that the sum of the successor of a and the successor of the numeral for n equals the successor of the sum of the successor of a and the numeral for n, by axiom Q subscript five. Step six, attributed in the source to the induction hypothesis. Q proves that the sum of the successor of a and the successor of the numeral for n equals the successor of the sum of a and the successor of the numeral for n. Final source line. Q proves that the successor of the sum of the successor of a and the numeral for n equals the successor of the sum of a and the successor of the numeral for n, by step five of the successor and fixed numeral addition derivation and step six of the successor and fixed numeral addition derivation

Means: Step five. Q proves that the sum of the successor of a and the successor of the numeral for n equals the successor of the sum of the successor of a and the numeral for n, by axiom Q subscript five. Step six, attributed in the source to the induction hypothesis. Q proves that the sum of the successor of a and the successor of the numeral for n equals the successor of the sum of a and the successor of the numeral for n. Final source line. Q proves that the successor of the sum of the successor of a and the numeral for n equals the successor of the sum of a and the successor of the numeral for n, by step five of the successor and fixed numeral addition derivation and step six of the successor and fixed numeral addition derivation

Equation form expr-bb4b3b3752cc45ed

(x<t)A(x)\bforall{x < t}{!A(x)}

Read as: for every x less than t, A of x

Means: for every x less than t, A of x

Equation form expr-bb73dc40dadf40d6

n¯=k¯n¯=k¯\eq[\num n'][\num k'] \lif \eq[\num n][\num k]

Read as: if the successor of the numeral for n equals the successor of the numeral for k, then the numeral for n equals the numeral for k

Means: if the successor of the numeral for n equals the successor of the numeral for k, then the numeral for n equals the numeral for k

Equation form expr-bbca117ccebff147

NA(n¯)\Sat{N}{!A(\num n)}

Read as: the standard model N satisfies A of the numeral for n

Means: the standard model N satisfies A of the numeral for n

Equation form expr-bc0533ea2b50cd8b

QAg(m¯,n¯,0)\Th{Q} \Proves !A_g(\num{m}, \num{n}, \Obj 0)

Read as: Q proves that A subscript g of the numeral for m, the numeral for n, and the object language constant zero

Means: Q proves that A subscript g of the numeral for m, the numeral for n, and the object language constant zero

Equation form expr-bc2ac1b4f5189864

1¯0\num 1 \ident \Obj 0'

Read as: the numeral for one is the successor of the object language constant zero

Means: the numeral for one is the successor of the object language constant zero

Equation form expr-be58d8ae65b26403

0\Obj{0}

Read as: the object language constant zero

Means: the object language constant zero

Equation form expr-be6439baf2b773eb

Qy(Ag(n¯,y)y=k¯)since Ag represents g, andQz(Af(k¯,z)z=m¯)since Af represents f. Using just a little bit of logic, we can show that alsoQz(y(Ag(n¯,y)Af(y,z))z=m¯).\Th{Q} & \Proves \lforall[y][(!A_g(\num{n}, y) \lif \eq[y][\num{k}])] \intertext{since $!A_g$ represents~$g$, and} \Th{Q} & \Proves \lforall[z][(!A_f(\num{k}, z) \lif \eq[z][\num{m}])] \intertext{since $!A_f$ represents~$f$. Using just a little bit of logic, we can show that also} \Th{Q} & \Proves \lforall[z][(\lexists[y][(!A_g(\num{n}, y) \land !A_f(y, z))] \lif \eq[z][\num{m}])].

Read as: Q proves: for every y, if A subscript g holds of the numeral for n and y, then y equals the numeral for k; since A subscript g represents g. And Q proves: for every z, if A subscript f holds of the numeral for k and z, then z equals the numeral for m; since A subscript f represents f. Using logic, Q also proves: for every z, if there exists y such that both A subscript g of the numeral for n and y, and A subscript f of y and z, then z equals the numeral for m

Means: Q proves: for every y, if A subscript g holds of the numeral for n and y, then y equals the numeral for k; since A subscript g represents g. And Q proves: for every z, if A subscript f holds of the numeral for k and z, then z equals the numeral for m; since A subscript f represents f. Using logic, Q also proves: for every z, if there exists y such that both A subscript g of the numeral for n and y, and A subscript f of y and z, then z equals the numeral for m

Equation form expr-be8dcefb61dddd9f

t1t_1

Read as: t subscript one

Means: t subscript one

Equation form expr-bf91a68806643b2d

(b+c)=0\eq[(b' + c')][\Obj 0']

Read as: the sum of the successor of b and the successor of c equals the successor of the object language constant zero

Means: the sum of the successor of b and the successor of c equals the successor of the object language constant zero

Equation form expr-bfd6ef7500b63b6e

Qt1t2\Th{Q} \Proves \eq/[t_1][t_2]

Read as: Q proves that t subscript one does not equal t subscript two

Means: Q proves that t subscript one does not equal t subscript two

Equation form expr-c0b85f68695529e7

Q(n¯=m¯1¯=1¯)\Th{Q} \Proves (\eq[\num{n}][\num{m}] \land \eq[\num{1}][\num{1}])

Read as: Q proves that both the numeral for n equals the numeral for m, and the numeral for one equals itself

Means: Q proves that both the numeral for n equals the numeral for m, and the numeral for one equals itself

Equation form expr-c130ae82020bfd16

m<nm < n

Read as: m is less than n

Means: m is less than n

Equation form expr-c1ebb646a2c7db63

d1=lcm(1,,j)d_1 = \lcm(1,\dots,j)

Read as: d subscript one equals the least common multiple of the integers one through j

Means: d subscript one equals the least common multiple of the integers one through j

Equation form expr-c3acc8569f115745

Π1\Pi_1

Read as: Pi one

Means: Pi one

Equation form expr-c42b3309bde3d651

(m¯×n¯)(\num{m} \times \num{n})

Read as: the object language product of the numeral for m and the numeral for n

Means: the object language product of the numeral for m and the numeral for n

Equation form expr-c47201f62ece94f0

Amult(x0,x1,y)y=(x0×x1).!A_{\Mult}(x_0, x_1, y) \ident y = (x_0 \times x_1).

Read as: A subscript Mult of x subscript zero, x subscript one, and y is the formula y equals the object language product of x subscript zero and x subscript one

Means: A subscript Mult of x subscript zero, x subscript one, and y is the formula y equals the object language product of x subscript zero and x subscript one

Equation form expr-c4a123c8c48e6b9b

QBT(e¯,n¯,s¯)\Th{Q} \Proves !B_T(\num{e}, \num{n}, \num{s})

Read as: Q proves that B subscript T applied to the numerals for e, n, and s

Means: Q proves that B subscript T applied to the numerals for e, n, and s

Equation form expr-c4f0cb271cf766e6

AχR(n0¯,,nk¯,1¯)!A_{\Char{R}}(\num{n_0}, \dots, \num{n_k}, \num{1})

Read as: A subscript characteristic function of R, applied to the numerals for n subscript zero through n subscript k, and the numeral for one

Means: A subscript characteristic function of R, applied to the numerals for n subscript zero through n subscript k, and the numeral for one

Equation form expr-c60dc090c13fb049

n1¯=n1¯\eq[\num{n_1}'][\num{n_1}']

Read as: the successor of the numeral for n subscript one equals the successor of the numeral for n subscript one

Means: the successor of the numeral for n subscript one equals the successor of the numeral for n subscript one

Equation form expr-c63f9557f464c93a

¬A\lnot !A

Read as: not A

Means: not A

Equation form expr-c69517800513e472

QAadd(n¯,m¯,k¯)\Th{Q} \Proves !A_\Add(\num{n}, \num{m}, \num{k})

Read as: Q proves that A subscript Add applied to the numeral for n, the numeral for m, and the numeral for k

Means: Q proves that A subscript Add applied to the numeral for n, the numeral for m, and the numeral for k

Equation form expr-c6af2de2cdedff23

Q(n¯+m¯)=n+m¯,\Th{Q} \Proves \eq[(\num{n}+\num{m})][\num{n+m}],

Read as: Q proves that the sum of the numeral for n and the numeral for m equals the numeral for n plus m

Means: Q proves that the sum of the numeral for n and the numeral for m equals the numeral for n plus m

Equation form expr-c6c006c35255f7a9

K(z)=(minxz)(yz)z=J(x,y),L(z)=(minyz)(xz)z=J(x,y);K(z) & = \bmin{x \leq z}{\bexists{y \leq z}{z = J(x,y)}},\\ L(z) & = \bmin{y \leq z}{\bexists{x \leq z}{z = J(x,y)}};

Read as: K of z equals the least x less than or equal to z such that there exists y less than or equal to z with z equal to J of x and y. L of z equals the least y less than or equal to z such that there exists x less than or equal to z with z equal to J of x and y

Means: K of z equals the least x less than or equal to z such that there exists y less than or equal to z with z equal to J of x and y. L of z equals the least y less than or equal to z such that there exists x less than or equal to z with z equal to J of x and y

Equation form expr-c6d8b66c8445862f

QxA(x)\Th{Q} \Proves \lexists[x][!A(x)]

Read as: Q proves that there exists x such that A of x

Means: Q proves that there exists x such that A of x

Equation form expr-c753fa04cc8febbe

s=#δ#,f(n0,,nk)s = \tuple{\Gn{\delta}, f(n_0, \dots, n_k)}

Read as: s equals the prime power code of the ordered pair consisting of the Goedel number of delta and the number f of n subscript zero through n subscript k

Means: s equals the prime power code of the ordered pair consisting of the Goedel number of delta and the number f of n subscript zero through n subscript k

Equation form expr-c7d7dc4c87e87988

R(x0,,xk)R(x_0, \dots, x_k)

Read as: R of x subscript zero through x subscript k

Means: R of x subscript zero through x subscript k

Equation form expr-c8296fead254de67

Qy((y<m¯m¯<y)y=m¯).\Th{Q} \Proves \lforall[y][((y < \num{m} \lor \num{m} < y) \lor \eq[y][\num{m}])].

Read as: Q proves that for every y, either y is less than the numeral for m, or the numeral for m is less than y, or y equals the numeral for m

Means: Q proves that for every y, either y is less than the numeral for m, or the numeral for m is less than y, or y equals the numeral for m

Equation form expr-c8cd3e05db71af27

ValN(t)=k+1\Value{t}{N} = k+1

Read as: the value of t in the standard model N equals k plus one

Means: the value of t in the standard model N equals k plus one

Equation form expr-c94e90881ad97613

AR(x0,,xk)!A_R(x_0, \dots, x_k)

Read as: A subscript R applied to x subscript zero through x subscript k

Means: A subscript R applied to x subscript zero through x subscript k

Equation form expr-c9da8b5c962314d2

j=max(n,a0+1,,an+1),j = \max(n,a_0+1,\dots,a_n+1),

Read as: j equals the maximum of n, a subscript zero plus one, and so on through a subscript n plus one

Means: j equals the maximum of n, a subscript zero plus one, and so on through a subscript n plus one

Equation form expr-ca52fdc0d544864c

(s)1(s)_1

Read as: the entry at position one in the prime power sequence coded by s

Means: the entry at position one in the prime power sequence coded by s

Equation form expr-ca978112ca1bbdca

aa

Read as: a

Means: a

Equation form expr-caa2c3f5df4bcdee

n+1k+1n+1 \neq k+1

Read as: n plus one does not equal k plus one

Means: n plus one does not equal k plus one

Equation form expr-cb38ea1ca94b6a4e

m+1¯<a\num{m+1} < a

Read as: the numeral for m plus one is less than a

Means: the numeral for m plus one is less than a

Equation form expr-cb91d6f4cdc873bb

Af(z,y)Ag(y,z,0)w(w<y¬Ag(w,z,0))!A_f(z,y) \ident !A_g(y, z, \Obj 0) \land \lforall[w][(w < y \lif \lnot !A_g(w, z, \Obj 0))]

Read as: A subscript f of z and y is the conjunction of A subscript g of y, z, and the object language constant zero, with the following universal statement: for every w, if w is less than y then not A subscript g of w, z, and the object language constant zero

Means: A subscript f of z and y is the conjunction of A subscript g of y, z, and the object language constant zero, with the following universal statement: for every w, if w is less than y then not A subscript g of w, z, and the object language constant zero

Equation form expr-cb9e98ffe227a219

Q(a+n¯)=(a+n¯).\Th{Q} \Proves \eq[(a' + \num n)][(a + \num n)'].

Read as: Q proves that the sum of the successor of a and the numeral for n equals the successor of the sum of a and the numeral for n

Means: Q proves that the sum of the successor of a and the numeral for n equals the successor of the sum of a and the numeral for n

Equation form expr-cc7fd1eac73960bb

y(Af(n0¯,,nk¯,y)m¯=y)\lforall[y][(!A_f(\num{n_0}, \dots, \num{n_k}, y) \lif \num{m} = y)]

Read as: for every y, if A subscript f holds of the numerals for n subscript zero through n subscript k, and y, then the numeral for m equals y

Means: for every y, if A subscript f holds of the numerals for n subscript zero through n subscript k, and y, then the numeral for m equals y

Equation form expr-cd0aa9856147b6c5

gg

Read as: g

Means: g

Equation form expr-cdd5f70c7ba98085

g(x,y,z)g(\vec x, y, z)

Read as: g of the tuple x, y, and z

Means: g of the tuple x, y, and z

Equation form expr-ce1dea246c115488

A(x,y)!A(x, y)

Read as: A of x and y

Means: A of x and y

Equation form expr-ce5499b301e3ff6e

h(e,n)={1if ProvQ(g(e,n))0otherwise.h(e, n) = \begin{cases} 1 & \text{if $\Prov[\Th{Q}](g(e, n))$}\\ 0 & \text{otherwise}. \end{cases}

Read as: h of e and n equals one if g of e and n is the Goedel number of a sentence provable in Q, and equals zero otherwise

Means: h of e and n equals one if g of e and n is the Goedel number of a sentence provable in Q, and equals zero otherwise

Equation form expr-cf9404d3f534ee7e

nkn_k

Read as: n subscript k

Means: n subscript k

Equation form expr-cfed7d5e81fdcd14

Q(a+n¯)=(a+n¯)\Th{Q} \Proves \eq[(a' + \num n)][(a + \num n)']

Read as: Q proves that the sum of the successor of a and the numeral for n equals the successor of the sum of a and the numeral for n

Means: Q proves that the sum of the successor of a and the numeral for n equals the successor of the sum of a and the numeral for n

Equation form expr-d055ee4dbcdd0c8b

B!B

Read as: B

Means: B

Equation form expr-d09ed1e4ecd2d22e

k=ValN(t)k=\Value{t}{N}

Read as: k equals the value of t in the standard model N

Means: k equals the value of t in the standard model N

Equation form expr-d0c0747b792ead99

R(n0,,nk)R(n_0,\dots,n_k)

Read as: R of n subscript zero through n subscript k

Means: R of n subscript zero through n subscript k

Equation form expr-d0f6b500e6a0f078

a<1¯a=0a < \num 1 \lif \eq[a][\Obj 0]

Read as: if a is less than the numeral for one, then a equals the object language constant zero

Means: if a is less than the numeral for one, then a equals the object language constant zero

Equation form expr-d16e8ab6de59c4c0

β(d,i)=β*(d0,d1,i)=rem(1+(i+1)d1,d0)=ai\beta(d,i) & = \beta^*(d_0,d_1,i) \\ & = \fn{rem}(1+(i+1) d_1,d_0) \\ & = a_i

Read as: Beta of d and i equals beta star of d subscript zero, d subscript one, and i. This equals the remainder when d subscript zero is divided by one plus the product of i plus one and d subscript one. This equals a subscript i

Means: Beta of d and i equals beta star of d subscript zero, d subscript one, and i. This equals the remainder when d subscript zero is divided by one plus the product of i plus one and d subscript one. This equals a subscript i

Equation form expr-d170031b3881cb44

Qn¯<k+1¯\Th{Q} \Proves \num n < \num{k+1}

Read as: Q proves that the numeral for n is less than the numeral for k plus one

Means: Q proves that the numeral for n is less than the numeral for k plus one

Equation form expr-d184b0662ef95fea

J(x,y)=12[(x+y)(x+y+1)]+xJ(x,y) = \frac{1}{2}[(x+y)(x+y+1)] + x

Read as: J of x and y equals one half of the product of x plus y and x plus y plus one, plus x

Means: J of x and y equals one half of the product of x plus y and x plus y plus one, plus x

Equation form expr-d203ba01eef4198c

δ\delta

Read as: delta

Means: delta

Equation form expr-d2088115bb6beae8

T!T

Read as: T

Means: T

Equation form expr-d216b49687a64c2b

χ=(x0,x1)={1if x0=x10otherwise\Char{=}(x_0, x_1) = \begin{cases} 1 & \text{if } x_0 =x_1\\ 0 & otherwise \end{cases}

Read as: The characteristic function of equality applied to x subscript zero and x subscript one has two cases: one if x subscript zero equals x subscript one; zero otherwise

Means: The characteristic function of equality applied to x subscript zero and x subscript one has two cases: one if x subscript zero equals x subscript one; zero otherwise

Equation form expr-d231f4622566655b

add(n,m)=k\Add(n, m) = k

Read as: the addition function applied to n and m equals k

Means: the addition function applied to n and m equals k

Equation form expr-d23482973ce32f15

(c+b)=n+1¯\eq[(c'+b)][\num{n+1}]

Read as: the sum of the successor of c and b equals the numeral for n plus one

Means: the sum of the successor of c and b equals the numeral for n plus one

Equation form expr-d30a1e55e70e9308

z+nm¯=0\eq[z' + \num{n - m}][\Obj 0]

Read as: the sum of the successor of z and the numeral for n minus m equals the object language constant zero

Means: the sum of the successor of z and the numeral for n minus m equals the object language constant zero

Equation form expr-d33d5093ec487a6e

Q4!Q_4

Read as: Q subscript four

Means: Q subscript four

Equation form expr-d3482b3a268726b8

n+m¯\num{n+m}

Read as: the numeral for n plus m

Means: the numeral for n plus m

Equation form expr-d37ee030798fd9cd

(d)i(d)_i

Read as: the entry beta of d and i in the beta coding

Means: the entry beta of d and i in the beta coding

Equation form expr-d3a9668f550f81b4

β(d,i)=ai\beta(d,i) = a_i

Read as: beta of d and i equals a subscript i

Means: beta of d and i equals a subscript i

Equation form expr-d438a18a7da07bf0

x<yx < y

Read as: x is less than y

Means: x is less than y

Equation form expr-d4735e3a265e16ee

22

Read as: two

Means: two

Equation form expr-d52d8099d5776fc7

A(n¯)!A(\num n)

Read as: A of the numeral for n

Means: A of the numeral for n

Equation form expr-d6a2d379cf7382cc

y=g(x)y = g(x)

Read as: y equals g of x

Means: y equals g of x

Equation form expr-d6c75f6e980ad53e

(x0+x1)=y(x_0 + x_1) = y

Read as: the sum of x subscript zero and x subscript one equals y

Means: the sum of x subscript zero and x subscript one equals y

Equation form expr-d6e7de4c36623607

Q(AB)\Th{Q} \Proves (!A \lor !B)

Read as: Q proves that A or B

Means: Q proves that A or B

Equation form expr-d73ac5aa141ceef8

(b+0)=a\eq[(b' + \Obj 0)][a]

Read as: the sum of the successor of b and the object language constant zero equals a

Means: the sum of the successor of b and the object language constant zero equals a

Equation form expr-d7716462fdf37ea7

pxip \mid x_i

Read as: p divides x subscript i

Means: p divides x subscript i

Equation form expr-d826a37801d792cd

ini \le n

Read as: i is less than or equal to n

Means: i is less than or equal to n

Equation form expr-d89ad7af62404a57

PA\Th{PA}

Read as: P A

Means: P A

Equation form expr-d99b5e7deabebeb1

h(x0,,xl1)=f(g0(x0,,xl1),,gk1(x0,,xl1)).h(x_0, \dots, x_{l-1}) = f(g_0(x_0, \dots, x_{l-1}), \dots, g_{k-1}(x_0, \dots, x_{l-1})).

Read as: h of x subscript zero through x subscript l minus one equals f applied to the outputs of g subscript zero through g subscript k minus one, each evaluated on that same input tuple x subscript zero through x subscript l minus one

Means: h of x subscript zero through x subscript l minus one equals f applied to the outputs of g subscript zero through g subscript k minus one, each evaluated on that same input tuple x subscript zero through x subscript l minus one

Equation form expr-dabd3aff769f07eb

<<

Read as: less than

Means: less than

Equation form expr-daf18e7eb8ca32c3

Af(n0¯,,nk¯,(s)1¯)!A_f(\num{n_0}, \dots, \num{n_k}, \num{(s)_1})

Read as: A subscript f applied to the numerals for n subscript zero through n subscript k, and the numeral for the entry at position one in the prime power sequence coded by s

Means: A subscript f applied to the numerals for n subscript zero through n subscript k, and the numeral for the entry at position one in the prime power sequence coded by s

Equation form expr-dc0460d416b96ec6

a=c\eq[a][c']

Read as: a equals the successor of c

Means: a equals the successor of c

Equation form expr-dc4f7e0ff5edebdc

β*(d0,d1,i)=rem(1+(i+1)d1,d0) andβ(d,i)=β*(K(d),L(d),i).\beta^*(d_0,d_1,i) & = \fn{rem}(1+(i+1) d_1,d_0) \text{ and}\\ \beta(d,i) & = \beta^*(K(d),L(d),i).

Read as: Beta star of d subscript zero, d subscript one, and i equals the remainder when d subscript zero is divided by one plus the product of i plus one and d subscript one. Beta of d and i equals beta star of K of d, L of d, and i

Means: Beta star of d subscript zero, d subscript one, and i equals the remainder when d subscript zero is divided by one plus the product of i plus one and d subscript one. Beta of d and i equals beta star of K of d, L of d, and i

Equation form expr-dcdf8b93520408f3

y0y_0

Read as: y subscript zero

Means: y subscript zero

Equation form expr-dddec4cec1599e3c

mult\Mult

Read as: the multiplication function

Means: the multiplication function

Equation form expr-ddfe3323228fd83c

ValN(t)=n\Value{t}{N} = n

Read as: the value of t in the standard model N equals n

Means: the value of t in the standard model N equals n

Equation form expr-de7d1b721a1e0632

ii

Read as: i

Means: i

Equation form expr-deacb637cca1832d

AχR(x0,,xk,y)!A_{\Char{R}}(x_0, \dots, x_k, y)

Read as: A subscript characteristic function of R, applied to x subscript zero through x subscript k, and y

Means: A subscript characteristic function of R, applied to x subscript zero through x subscript k, and y

Equation form expr-deee498cab971fab

χ=\Char{=}

Read as: the characteristic function of equality

Means: the characteristic function of equality

Equation form expr-e0822a0f0cbced9e

f(x0,,xk)f(x_0,\ldots,x_k)

Read as: f of x subscript zero through x subscript k

Means: f of x subscript zero through x subscript k

Equation form expr-e1636b0d23d218c1

n+k+1=mn + k + 1 = m

Read as: n plus k plus one equals m

Means: n plus k plus one equals m

Equation form expr-e1ff22673febf333

0¯1¯\eq/[\num{0}][\num{1}]

Read as: the numeral for zero does not equal the numeral for one

Means: the numeral for zero does not equal the numeral for one

Equation form expr-e246d1ddfd2bc6f7

{A:QA}\Setabs{!A}{\Th{Q} \Proves !A}

Read as: the set of formulas A such that Q proves A

Means: the set of formulas A such that Q proves A

Equation form expr-e30d2435124a07e9

l=f(n0,,nk)l = f(n_0, \dots, n_k)

Read as: l equals f of n subscript zero through n subscript k

Means: l equals f of n subscript zero through n subscript k

Equation form expr-e3212229d200318d

¬B\lnot !B

Read as: not B

Means: not B

Equation form expr-e35c9e414191ba7e

(n¯=m¯y=1¯)(n¯m¯y=0¯)(\eq[\num{n}][\num{m}] \land \eq[y][\num{1}]) \lor (\eq/[\num{n}][\num{m}] \land \eq[y][\num{0}])

Read as: either the numeral for n equals the numeral for m and y equals the numeral for one; or the numeral for n does not equal the numeral for m and y equals the numeral for zero

Means: either the numeral for n equals the numeral for m and y equals the numeral for one; or the numeral for n does not equal the numeral for m and y equals the numeral for zero

Equation form expr-e3b98a4da31a127d

tt

Read as: t

Means: t

Equation form expr-e49d8938325a43e0

n=ValN(t1)n = \Value{t_1}{N}

Read as: n equals the value of t subscript one in the standard model N

Means: n equals the value of t subscript one in the standard model N

Equation form expr-e4c5ac9c0248aa1c

t1<t2t_1 < t_2

Read as: t subscript one is less than t subscript two

Means: t subscript one is less than t subscript two

Equation form expr-e4d2363b6ce3190e

h(x)=zh(x) = z

Read as: h of x equals z

Means: h of x equals z

Equation form expr-e5f403ce29d1c8e6

y=1¯\eq[y][\num{1}]

Read as: y equals the numeral for one

Means: y equals the numeral for one

Equation form expr-e632b7095b0bf32c

TT

Read as: T

Means: T

Equation form expr-e6ac6aa77892e7e2

(c+m+1¯)=a\eq[(c' + \num{m+1})][a]

Read as: the sum of the successor of c and the numeral for m plus one equals a

Means: the sum of the successor of c and the numeral for m plus one equals a

Equation form expr-e6c5f5f3979df938

1+d11+d_1

Read as: one plus d subscript one

Means: one plus d subscript one

Equation form expr-e6d166895851cb40

QA(0¯)A(k¯)\Th{Q} \Proves !A(\num 0) \land \dots \land !A(\num k)

Read as: Q proves that A holds of every numeral from zero through k, as a finite conjunction

Means: Q proves that A holds of every numeral from zero through k, as a finite conjunction

Equation form expr-e71563ff05fb591e

n¯+m¯=n+m¯ andy((n¯+m¯)=yy=n+m¯).& \eq[\num n + \num m][\num {n+m}] \text{ and}\\ & \lforall[y][(\eq[(\num n + \num m)][y] \lif \eq[y][\num{n+m}])].

Read as: The sum of the numeral for n and the numeral for m equals the numeral for the number n plus m. And for every y, if that sum equals y, then y equals the numeral for n plus m

Means: The sum of the numeral for n and the numeral for m equals the numeral for the number n plus m. And for every y, if that sum equals y, then y equals the numeral for n plus m

Equation form expr-e7e3a5dd1bed8a04

(b+c)=0\eq[(b'+c)'][\Obj 0']

Read as: the successor of the sum of the successor of b and c equals the successor of the object language constant zero

Means: the successor of the sum of the successor of b and c equals the successor of the object language constant zero

Equation form expr-e8c17252cf9632d5

χR\Char{R}

Read as: the characteristic function of R

Means: the characteristic function of R

Equation form expr-e9079c14e05d0693

Qn¯m¯\Th{Q} \Proves \eq/[\num n][\num m]

Read as: Q proves that the numeral for n does not equal the numeral for m

Means: Q proves that the numeral for n does not equal the numeral for m

Equation form expr-e9ccc382bd3f2395

z(z+b)=m¯\lexists[z][\eq[(z' + b)][\num{m}]]

Read as: there exists z such that the sum of the successor of z and b equals the numeral for m

Means: there exists z such that the sum of the successor of z and b equals the numeral for m

Equation form expr-e9ebe3576784cff0

n+m+1¯\num{n+m+1}

Read as: the numeral for n plus m plus one

Means: the numeral for n plus m plus one

Equation form expr-ea1b0f85ed186853

Qt1=n¯1\Th{Q} \Proves \eq[t_1][\num n_1]

Read as: Q proves that t subscript one equals the numeral for n subscript one

Means: Q proves that t subscript one equals the numeral for n subscript one

Equation form expr-ea2d8c8da4f6c79a

Q(x<t)A(x)\Th{Q} \Proves \bforall{x<t}{!A(x)}

Read as: Q proves that for every x less than t, A of x

Means: Q proves that for every x less than t, A of x

Equation form expr-ea7df4bc96e2f1e1

APin(x0,,xn1,y)y=xi.!A_{\Proj{n}{i}}(x_0, \dots, x_{n-1}, y) \ident \eq[y][x_i].

Read as: A subscript projection function with arity n and index i, applied to x subscript zero through x subscript n minus one and y, is the formula y equals x subscript i

Means: A subscript projection function with arity n and index i, applied to x subscript zero through x subscript n minus one and y, is the formula y equals x subscript i

Equation form expr-eaea22e02f98a7a8

x0=yx_0' = y

Read as: the successor of x subscript zero equals y

Means: the successor of x subscript zero equals y

Equation form expr-eb2e661237ddf347

ValN(t2)=n2\Value{t_2}{N} = n_2

Read as: the value of t subscript two in the standard model N equals n subscript two

Means: the value of t subscript two in the standard model N equals n subscript two

Equation form expr-ec76e63a46b447fc

i<yi < y

Read as: i is less than y

Means: i is less than y

Equation form expr-eda0b1a24e71fdef

Q2Q_2

Read as: Q subscript two

Means: Q subscript two

Equation form expr-ee09bac82bcf2ecc

Qx¬x<0\Th{Q} \Proves \lforall[x][\lnot x < \Obj 0]

Read as: Q proves that for every x, it is not the case that x is less than the object language constant zero

Means: Q proves that for every x, it is not the case that x is less than the object language constant zero

Equation form expr-ee3f045c61a5cba0

nkn \leq k

Read as: n is less than or equal to k

Means: n is less than or equal to k

Equation form expr-ef42aeac157b2180

QyBT(e¯,n¯,y)\Th{Q} \Proves \lexists[y][!B_T(\num{e}, \num{n}, y)]

Read as: Q proves that there exists y such that B subscript T holds of the numeral for e, the numeral for n, and y

Means: Q proves that there exists y such that B subscript T holds of the numeral for e, the numeral for n, and y

Equation form expr-ef5d0009ab633762

At1<t2!A \ident t_1 < t_2

Read as: A is the formula t subscript one is less than t subscript two

Means: A is the formula t subscript one is less than t subscript two

Equation form expr-f03c4223d0e0061d

Q¬A\Th{Q} \Proves \lnot !A

Read as: Q proves that not A

Means: Q proves that not A

Equation form expr-f091204a20056317

b=0b=n¯\eq[b'][\Obj 0'] \lor \dots \lor \eq[b'][\num{n}']

Read as: the successor of b equals one of the successors of the numerals from zero through n

Means: the successor of b equals one of the successors of the numerals from zero through n

Equation form expr-f29d3f9eef64b9fd

b0\eq/[b'][\Obj 0]

Read as: the successor of b does not equal the object language constant zero

Means: the successor of b does not equal the object language constant zero

Equation form expr-f345e4b35fa6a724

h(x,0),h(x,1),,h(x,y)\tuple{h(\vec x, 0), h(\vec x, 1), \dots, h(\vec x, y)}

Read as: the sequence consisting of h of the tuple x and zero, h of the tuple x and one, and so on through h of the tuple x and y

Means: the sequence consisting of h of the tuple x and zero, h of the tuple x and one, and so on through h of the tuple x and y

Equation form expr-f3e60deab2094406

k¯\num k

Read as: the numeral for k

Means: the numeral for k

Equation form expr-f3f3804480e8551a

β\beta

Read as: beta

Means: beta

Equation form expr-f476b622c6193985

y(AχR(n0¯,,nk¯,y)y=0¯).\lforall[y][(!A_{\Char{R}}(\num{n_0}, \dots, \num{n_k}, y) \lif y = \num{0})].

Read as: for every y, if A subscript characteristic function of R holds of the numerals for n subscript zero through n subscript k, and y, then y equals the numeral for zero

Means: for every y, if A subscript characteristic function of R holds of the numerals for n subscript zero through n subscript k, and y, then y equals the numeral for zero

Equation form expr-f47dcc537d15d65c

y(Ag(x,y)Af(y,z))\lexists[y][(!A_g(x, y) \land !A_f(y, z))]

Read as: the existential formula with bound variable y and matrix consisting of A subscript g of x and y, conjoined with A subscript f of y and z

Means: the existential formula with bound variable y and matrix consisting of A subscript g of x and y, conjoined with A subscript f of y and z

Equation form expr-f54fef43dc45d2b2

b=m¯\eq[b][\num{m}]

Read as: b equals the numeral for m

Means: b equals the numeral for m

Equation form expr-f6d7e6e92d70c039

0\Obj{0}^{\prime\prime\ldots\prime}

Read as: the object language constant zero followed by the displayed sequence of successor marks

Means: the object language constant zero followed by the displayed sequence of successor marks

Equation form expr-f6e29a7cebc04e20

m·nm \cdot n

Read as: m times n

Means: m times n

Equation form expr-f88d3cb081b9e7f7

Qzz+t1=t2\Th{Q} \Proves \lexists[z][\eq[z' + t_1][t_2]]

Read as: Q proves that there exists z such that the sum of the successor of z and t subscript one equals t subscript two

Means: Q proves that there exists z such that the sum of the successor of z and t subscript one equals t subscript two

Equation form expr-f891973c7e4f4f94

(n¯=n¯y=1¯)(n¯n¯y=0¯)(\eq[\num{n}][\num{n}] \land \eq[y][\num{1}]) \lor (\eq/[\num{n}][\num{n}] \land \eq[y][\num{0}])

Read as: either the numeral for n equals itself and y equals the numeral for one; or the numeral for n does not equal itself and y equals the numeral for zero

Means: either the numeral for n equals itself and y equals the numeral for one; or the numeral for n does not equal itself and y equals the numeral for zero

Equation form expr-f921fe1caca7cb62

¬a<0\lnot a < \Obj 0

Read as: it is not the case that a is less than the object language constant zero

Means: it is not the case that a is less than the object language constant zero

Equation form expr-f96d7ac361383f38

¬AR(n0¯,,nk¯)\lnot !A_R(\num{n_0}, \dots, \num{n_k})

Read as: not A subscript R applied to the numerals for n subscript zero through n subscript k

Means: not A subscript R applied to the numerals for n subscript zero through n subscript k

Equation form expr-fa3ca3612e44b977

(c+b)=m¯\eq[(c' + b)'][\num{m}']

Read as: the successor of the sum of the successor of c and b equals the successor of the numeral for m

Means: the successor of the sum of the successor of c and b equals the successor of the numeral for m

Equation form expr-fa9afbb163c9a35d

(a+n¯)=(a+n¯)\eq[(a' + \num{n}')][(a + \num{n}')']

Read as: the sum of the successor of a and the successor of the numeral for n equals the successor of the sum of a and the successor of the numeral for n

Means: the sum of the successor of a and the successor of the numeral for n equals the successor of the sum of a and the successor of the numeral for n

Equation form expr-fab1ef2eb664e0ce

Subst\fn{Subst}

Read as: the substitution coding function Subst

Means: the substitution coding function Subst

Equation form expr-fcfea66fe1902321

not(x)=χ=(x,0)(minxz)R(x,y)=μx(R(x,y)x=z)(xz)R(x,y)R((minxz)R(x,y),y)\fn{not}(x) & \defis \Char{=}(x,0)\\ \bmin{x \leq z}{R(x,y)} & \defis \umin{x}{(R(x,y) \lor x = z)}\\ \bexists{x \leq z}{R(x,y)} & \defiff R(\bmin{x \leq z}{R(x,y)}, y)

Read as: Three definitions without primitive recursion. Not of x is defined to be the characteristic function of equality applied to x and zero. The bounded minimum of x less than or equal to z such that R of x and y is defined to be the least x such that either R of x and y or x equals z. The bounded existential statement that there is x less than or equal to z such that R of x and y holds is defined to mean that R holds of that bounded minimum and y. End of the three definitions

Means: Three definitions without primitive recursion. Not of x is defined to be the characteristic function of equality applied to x and zero. The bounded minimum of x less than or equal to z such that R of x and y is defined to be the least x such that either R of x and y or x equals z. The bounded existential statement that there is x less than or equal to z such that R of x and y holds is defined to mean that R holds of that bounded minimum and y. End of the three definitions

Equation form expr-fdc3cd2160233f3d

n¯k¯\eq/[\num n'][\num k']

Read as: the successor of the numeral for n does not equal the successor of the numeral for k

Means: the successor of the numeral for n does not equal the successor of the numeral for k

Equation form expr-fdc5b3ea336decbd

Q¬B\Th{Q} \Proves \lnot !B

Read as: Q proves that not B

Means: Q proves that not B

Equation form expr-ff9ba27416d63e9a

(AB)(!A \land !B)

Read as: the conjunction of A and B

Means: the conjunction of A and B

Eight axioms of Robinson arithmetic Q

The eight universally quantified axioms govern successor injectivity, zero not being a successor, every nonzero object being a successor, recursive addition and multiplication, and less than. The associated expression reads every axiom and its label in order. There is no induction axiom here.

Source

Representability of a numerical function in Q

A formula with input variables and one output variable represents a function when, for each actual input tuple and output value, Q proves the formula on the corresponding numerals and proves that any output satisfying it equals that output numeral. Both clauses are required; the universal uniqueness clause is inside Q, while the choice of numerical inputs is metatheoretic.

Source

Functions representable in Q are exactly the computable functions

The theorem has two directions. The chapter first computes representable functions by searching through coded proofs, then represents all general recursive functions using basic arithmetic functions, composition, and regular minimization. The theorem is stated here and proved by the subsequent sections.

Source

Provable instances of a representing formula identify the correct value

For a function represented in Q, the instance of its representing formula on input and output numerals is provable exactly when that output is the actual function value. The source proof combines representability, uniqueness, provability of inequality of distinct numerals, and consistency of Q from its standard model.

Source

Every function representable in Q is computable

The proof first describes a search for a derivation of a numeral instance of the representing formula. It then makes the search numerical using substitution codes, the primitive recursive proof relation, and regular minimization of codes of proof and output pairs. A proof exists for every input, and the preceding lemma ensures that its output is correct.

Source

Nested substitutions defining the numeral instance code

Start with the Goedel number of the representing formula. Substitute the appropriate numeral code for each input variable in order, then the output numeral code for the output variable. The display is a nested functional definition, not a derivation tree. The associated speech preserves the distinction between each numerical input, its numeral, and that numeral code.

Source

The beta function lemma

There is a function beta such that every finite sequence can be decoded from some natural number d: beta of d and i returns the entry at position i. Beta is definable using basic functions, composition, and regular minimization, without primitive recursion. This coding is explicitly different from the earlier prime power coding. The lemma asserts existence of a suitable code, not an algorithm constructing that code within the restricted resources.

Source

Relatively prime natural numbers

Two natural numbers are relatively prime when their greatest common divisor is one. The definition concerns common divisors; it does not require that either number itself be prime.

Source

Congruence modulo a natural number

The definition says that a and b are congruent modulo c when c divides their difference, equivalently when they have the same remainder on division by c. The modular parameter and the direction of division are retained.

Source

Sunzi theorem on simultaneous congruences

Given pairwise relatively prime moduli x subscript zero through x subscript n and arbitrary residues y subscript zero through y subscript n, there exists a number z satisfying all the displayed congruences simultaneously. The source also identifies this as the theorem traditionally called the Chinese Remainder Theorem.

Source

System of simultaneous congruences

Every row uses the same unknown z. Row i says that z is congruent to y subscript i modulo x subscript i, for indices zero through n. The rows are simultaneous conditions, not successive transformations of z.

Source

Choice of bounds and common multiple for sequence coding

j is the maximum of n and one greater than each proposed residue. m is the least common multiple of the integers from one through j. These choices are used to construct moduli larger than their residues and pairwise relatively prime.

Source

The chosen family of moduli

The modulus with index i is one plus the product of i plus one and m. The display gives the first three members and the final member. Its continuation preserves both the index shift by one and the added one outside the product.

Source

Negation and bounded operations from minimization

Three displayed definitions express the numerical Boolean not function, a bounded minimum with endpoint fallback, and a bounded existential relation. The last definition tests R at the bounded minimum. The endpoint z ensures termination of the unbounded search used inside the bounded minimum.

Source

The two inverse coordinate functions of the pairing map

K searches for the first coordinate of a pair coded by z; L searches for the second. Each search and its witnessing quantifier is bounded by z. Both tests use the same pairing function J with its argument order x then y.

Source

Definitions of beta star and beta

Beta star takes a residue code, a modulus spacing parameter, and an index, and returns the remainder modulo one plus the product of the index plus one and the spacing parameter. Beta first extracts the two coordinates of d using K and L. The first argument of rem is the divisor, not the dividend.

Source

Verification that beta returns the chosen sequence entry

The three equal quantities are beta of d and i, beta star of the two coordinates and i, and the appropriate remainder, which equals a subscript i. Sunzi theorem and the previously selected bounds supply the final equality.

Source

Exercise defining order divisibility and remainder without primitive recursion

The source asks the reader to define less than, divisibility, and rem without primitive recursion. The permitted resources are zero, successor, addition, multiplication, the characteristic function of equality, projections, bounded minimization, and bounded quantification. No solution is supplied here.

Source

Primitive recursion equations for h

The base value at last argument zero is f of the parameter tuple. The value at last argument y plus one is g of the parameter tuple, y, and the previous value h at y. The parameter tuple is unchanged in both equations.

Source

Simulation of primitive recursion by regular minimization

A function defined by primitive recursion from f and g can instead be defined using those functions, zero, successor, projections, addition, multiplication, the characteristic function of equality, composition, and regular minimization. The proof searches for a beta code of a finite sequence satisfying the recursion and then decodes its last entry.

Source

Two requirements for representing addition

The first requirement states the correct sum of two numerals. The second universally quantifies the output variable and says any output equal to that sum equals the numeral of the numerical sum. These are the value and uniqueness conditions for representability.

Source

Representability of the zero function

The zero function maps every input to zero. Its representing formula says that the output variable equals the object language constant zero. The input variable need not occur in this formula.

Source

Representability of the successor function

The successor function maps x to x plus one. Its representing formula says that the output variable equals the successor term on the input variable.

Source

Representability of projection functions

The projection function with arity n and index i returns input coordinate i. Its representing formula states equality of the output variable with that coordinate. The indexing runs from zero to n minus one.

Source

Exercise proving representability of the three initial functions

Prove that the three displayed equality formulas represent zero, successor, and the indicated projection, respectively. The proof is left to the reader; no solution is added.

Source

Representability of the characteristic function of equality

The numerical function returns one for equal inputs and zero otherwise. The representing formula is a disjunction: equal input terms together with output numeral one, or unequal input terms together with output numeral zero. The proof separates the equal and unequal cases and verifies uniqueness in each.

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Q proves inequality of distinct numerals

For any two distinct natural numbers, Q proves that their numerals are unequal. The proof is by external induction on one of the numbers, using the successor axioms. It does not assert that Q internally proves a universally quantified inequality principle by induction.

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Representability of addition

The numerical addition function is represented by equality between the output variable and the object language sum of the two input variables. The following numerical evaluation lemma supplies the value condition, and equality reasoning supplies uniqueness.

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Q computes each sum of numerals

Q proves that the object language sum of the numeral for n and the numeral for m equals the numeral for the number n plus m. The proof uses external induction on m, with the zero and successor axioms for addition.

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Representability of multiplication

The numerical multiplication function is represented by equality between the output variable and the object language product of the input variables. The proof is marked Exercise in the source and remains unsolved.

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Q computes each product of numerals

Q proves that the object language product of the numerals for n and m equals the numeral for their numerical product. The proof is marked Exercise in the source and is not filled in.

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Exercise proving the numeral multiplication lemma

Prove the preceding lemma that Q evaluates products of numerals. The lemma reference is retained, and the source exercise remains unsolved.

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Exercise proving representability of multiplication

Use the numeral multiplication lemma to prove representability of multiplication. Both source references are retained; no new proof is supplied.

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Composition satisfies the value clause of representability

For the unary composition h of x equal to f of g of x, whenever h of n equals m, Q proves the proposed representing formula on the numerals for n and m. The proof uses the actual intermediate value k equal to g of n as an existential witness.

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Deriving the correct numeral instance for composition

Q proves the two representing instances for g and f, then their conjunction, then existentially quantifies the intermediate value. Interleaved source explanations identify which representing formula justifies each initial instance. The displayed steps form a linear derivation.

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Composition satisfies the uniqueness clause of representability

When h of n equals m, Q proves that every output z satisfying the proposed formula for h equals the numeral for m. The proof applies the uniqueness properties of g and f in sequence.

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Deriving uniqueness for a composition

The first universal statement forces the intermediate variable y to equal the numeral for k. The second forces z to equal the numeral for m. Logic then yields the universal uniqueness statement for the existentially composed formula. Quantifier scopes remain attached to their own conclusions.

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Representability is preserved under general composition

For a function f of k inputs and inner functions each of l inputs, existentially bind k intermediate variables. Conjoin every representing formula for the inner functions at the shared input tuple with the representing formula for f at those intermediate values and the output. The proof is marked Exercise and remains unsolved.

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Formula representing a general composition

There is one existential intermediate variable for each inner function. All inner representing formulas and the outer representing formula belong within the scope of all these quantifiers. The displayed ellipsis abbreviates the intervening conjunctions in index order.

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Exercise proving representability under general composition

Give the detailed proof of representability for general composition, using the preceding unary arguments as a guide. The source repeats the reference to the uniqueness proposition; that source reference defect is disclosed rather than silently changed. No solution is supplied.

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Moving successor past addition by a fixed numeral

For any constant a and natural number n, Q proves that the sum of the successor of a and the numeral for n equals the successor of the sum of a and that numeral. The parentheses are essential: the successor on the right applies to the whole sum. The source inductive derivation has a disclosed misidentified step and is preserved without a replacement proof.

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Base case of the fixed numeral successor identity

Two instances of the addition zero axiom identify the two sums. Applying successor to one equality and combining equalities gives the target base case. Four displayed lines retain their step labels and dependencies.

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Source inductive steps for the fixed numeral successor identity

The source presents step five from the addition successor axiom, step six attributed to induction, and a final equality attributed to both steps. The line labeled step six is already the desired successor case rather than the induction hypothesis. The source lines and this caveat are preserved; they are not treated as an independently verified proof.

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Q proves that nothing is less than zero

The lemma universally negates being less than the object language constant zero. The source proof expands the definition of less than, separates the zero and successor cases, and derives contradictions with the zero and successor axioms.

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Every object below a numeral is one of finitely many numerals

For every natural number n, Q proves that anything less than the numeral for n plus one equals one of the numerals zero through n. The external induction establishes a finite disjunction inside Q for each chosen bound.

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Trichotomy against each fixed numeral

For every natural number m, Q proves that each y is less than the numeral for m, greater than it, or equal to it. This is a separate provability claim for each numeral, proved by external induction; it is not stated as unrestricted internal trichotomy for two arbitrary variables.

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Induction hypothesis and target for fixed numeral trichotomy

The first displayed universal trichotomy is against the numeral for m. The second, introduced as the goal, is against the numeral for m plus one. Each has the same three alternatives in the same order.

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Representability is preserved under regular minimization

Given the representing formula for a regular function g, the formula for its least zero requires g to have value zero at the proposed output and not to have value zero at any smaller number. The universal bounded condition ensures leastness. The surrounding hypothesis of regularity ensures the numerical function is total.

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The value clause for the minimizing formula

The derivation combines the provable zero instance at the actual minimum with the negations of all smaller numeral instances. The finite numeral bound lemmas then yield the universal statement excluding every smaller object. Source explanations between rows are part of the linear reading, not omitted captions.

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Every computable function is representable in Q

Using general recursive functions as the precise model of computation, replace primitive recursion with the established simulation, represent each basic function, and apply closure under composition and regular minimization. The accompanying discussion distinguishes representability from the strength of a theory in proving arbitrary sentences.

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Representability of relations in Q

A formula represents a relation when Q proves its numeral instance whenever the relation holds, and proves the negation of that instance whenever the relation does not hold. Both positive and negative instances are required.

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Relations representable in Q are exactly the computable relations

The forward direction searches in parallel for a proof of the positive or negative instance. The backward direction represents the computable characteristic function and fixes its output argument to numeral one. Its unique output zero in the false case gives the required negative instance.

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Exercise relating representability of a relation and its characteristic function

Show that representability of R implies representability of its characteristic function. The source leaves this direction as an exercise, and no proof is added.

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Undecidability of Q

The provability relation restricts y to sentence codes and asserts existence of a derivation code in Q. The theorem says this relation is not recursive. The proof reduces halting to whether a sentence asserting a Kleene T witness is provable, using the standard model of Q to exclude false existential conclusions.

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Undecidability of first order logic

Because Q has finitely many axioms, provability from Q can be reduced to logical provability of an implication whose antecedent is the conjunction of those axioms. A decision procedure for first order logic would therefore decide Q, contradicting the preceding theorem.

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Bounded existential and universal formulas

A bounded existential requires both x less than its bound and A of x. A bounded universal says that x less than the bound implies A of x. Their compact bounded quantifier notations preserve these different connectives. The usual restriction that the bound not depend on the quantified variable is not stated in the source, and this omission is disclosed.

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Delta zero Sigma one and Pi one formulas

Delta zero formulas are built from atomic formulas by propositional connectives and bounded quantification. In the displayed definitions a Sigma one formula has an existential quantifier before a Delta zero formula, while a Pi one formula has a universal quantifier before a Delta zero formula.

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Q proves each closed term equal to its standard numeral

For a closed arithmetic term whose value in the standard model is n, Q proves its equality with the numeral for n. The proof uses structural induction on terms, the equality rules, and the previously established numeral arithmetic facts. The multiplication case is explicitly left for the following exercise.

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Exercise for the multiplication case of closed term evaluation

Give the detailed multiplication case of the closed term evaluation lemma. The source reference and the multiplication symbol are retained, and no solution is added.

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Atomic completeness for closed arithmetic terms

Four clauses cover equal standard values, unequal standard values, strict less than, and failure of strict less than. They conclude provability in Q of the corresponding equality, inequality, order statement, or negated order statement. The source proof contains a numeral index typo and incorrect contradiction axiom references; these are disclosed without claiming the printed steps are correct.

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Bounded quantification over a closed term reduces to a finite combination

If the closed bound has standard value k, a bounded universal is provable exactly when the conjunction of its numeral instances from zero through k minus one is provable. The existential counterpart uses their disjunction. The source proof treats the universal case and leaves the existential case to an exercise. Its zero bound paragraph misnames the empty conjunction as a disjunction; the mismatch is disclosed.

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Exercise proving the bounded existential equivalence

Give the detailed existential case of the bounded quantifier equivalence lemma. The exercise remains unsolved.

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Delta zero completeness of Q

Every Delta zero sentence true in the standard model is provable in Q. The source proof proceeds by formula complexity, separates positive and negated connective cases, reduces bounded quantifiers to finite combinations, and handles atomic negations and double negation. It leaves the detailed existential case for the following exercise.

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Exercise proving the existential case of Delta zero completeness

Give the detailed existential case of the Delta zero completeness lemma. No solution is supplied in the source or added by this edition.

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Sigma one completeness of Q

Every Sigma one sentence true in the standard model is provable in Q. Choose its standard numerical witness, substitute the corresponding numeral into the Delta zero matrix, apply Delta zero completeness, and introduce the existential quantifier. The source satisfaction statement explicitly uses assignment s for the free variable before numeral substitution.

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Cross-reference reference-000672

the definition of function representability in Q

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Cross-reference reference-000673

its first clause, proving the correct numeral instance

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Cross-reference reference-000674

the definition of function representability in Q

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Cross-reference reference-000675

its first clause, proving the correct numeral instance

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Cross-reference reference-000676

the definition of function representability in Q

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Cross-reference reference-000677

its second clause, proving uniqueness of the output

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Cross-reference reference-000678

the lemma that Q proves distinct numerals unequal

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Cross-reference reference-000679

the definition of the standard model of arithmetic

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Cross-reference reference-001840

the soundness corollary that satisfiable theories are consistent, for axiomatic derivations

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Cross-reference reference-001841

the soundness corollary that satisfiable theories are consistent, for sequent calculus

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Cross-reference reference-001842

the soundness corollary that satisfiable theories are consistent, for natural deduction

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Cross-reference reference-001843

the soundness corollary that satisfiable theories are consistent, for tableaux

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Cross-reference reference-000680

the lemma equating provable representing instances with correct function values

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Cross-reference reference-000681

the lemma equating provable representing instances with correct function values

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Cross-reference reference-000682

the proposition that numeral coding is primitive recursive

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Cross-reference reference-000683

the proposition that substitution coding is primitive recursive

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Cross-reference reference-000684

the first observation, that the chosen moduli are relatively prime

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Cross-reference reference-000685

the second observation, that each residue is smaller than its modulus

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Cross-reference reference-000686

the first observation, that the chosen moduli are relatively prime

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Cross-reference reference-000687

the second observation, that each residue is smaller than its modulus

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Cross-reference reference-000688

the beta function lemma

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Cross-reference reference-000689

the proposition representing the characteristic function of equality

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Cross-reference reference-000690

the lemma that Q proves distinct numerals unequal

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Cross-reference reference-000691

the lemma that Q proves distinct numerals unequal

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Cross-reference reference-000692

the proposition representing addition

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Cross-reference reference-000693

the lemma that Q computes sums of numerals

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Cross-reference reference-000694

the lemma that Q computes products of numerals

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Cross-reference reference-000695

the lemma that Q computes products of numerals

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Cross-reference reference-000696

the proposition representing multiplication

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Cross-reference reference-000697

the proposition giving the uniqueness clause for unary composition

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Cross-reference reference-000698

the proposition giving the uniqueness clause for unary composition

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Cross-reference reference-000699

the proposition representing general composition

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Cross-reference reference-000700

step two of the successor and fixed numeral addition derivation

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Cross-reference reference-000701

step one of the successor and fixed numeral addition derivation

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Cross-reference reference-000702

step three of the successor and fixed numeral addition derivation

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Cross-reference reference-000703

step five of the successor and fixed numeral addition derivation

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Cross-reference reference-000704

step six of the successor and fixed numeral addition derivation

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Cross-reference reference-000705

the lemma that Q proves nothing is less than zero

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Cross-reference reference-000706

the lemma that Q proves nothing is less than zero

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Cross-reference reference-000707

the lemma enumerating the objects less than a fixed numeral

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Cross-reference reference-000708

the lemma on trichotomy against each fixed numeral

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Cross-reference reference-000709

the displayed proof excluding all values below the minimum

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Cross-reference reference-000710

the lemma simulating primitive recursion by regular minimization

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Cross-reference reference-000711

the proposition representing the zero function

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Cross-reference reference-000712

the proposition representing the successor function

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Cross-reference reference-000713

the proposition representing projection functions

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Cross-reference reference-000714

the proposition representing the characteristic function of equality

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Cross-reference reference-000715

the proposition representing addition

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Cross-reference reference-000716

the proposition representing multiplication

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Cross-reference reference-000717

the proposition representing general composition

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Cross-reference reference-000718

the proposition representing regular minimization

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Cross-reference reference-000719

the theorem that function representability in Q is equivalent to computability

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Cross-reference reference-000720

Kleene normal form theorem

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Cross-reference reference-000721

the theorem that the halting problem is not computable

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Cross-reference reference-000722

the theorem on Sigma one completeness of Q

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Cross-reference reference-000723

the lemma that Q computes sums of numerals

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Cross-reference reference-000724

the lemma that Q computes products of numerals

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Cross-reference reference-000725

the closed term evaluation lemma

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Cross-reference reference-000726

the closed term evaluation lemma

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Cross-reference reference-000727

the closed term evaluation lemma

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Cross-reference reference-000728

the lemma that Q proves nothing is less than zero

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Cross-reference reference-000729

the closed term evaluation lemma

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Cross-reference reference-000730

the atomic completeness lemma

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Cross-reference reference-000731

the lemma enumerating the objects less than a fixed numeral

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Cross-reference reference-000732

the bounded quantifier equivalence lemma

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Cross-reference reference-000733

the atomic completeness lemma

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Cross-reference reference-000734

the bounded quantifier equivalence lemma

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Cross-reference reference-000735

the atomic completeness lemma

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Cross-reference reference-000736

the Delta zero completeness lemma

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Cross-reference reference-000737

the Delta zero completeness lemma

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Source disclosures