Expression 1
Conventional reading: conjunction
Meaning here: The binary logical connective and, used to form a conjunction.
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Syntax and Semantics
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Conventional reading: conjunction
Meaning here: The binary logical connective and, used to form a conjunction.
Conventional reading: A sub k
Meaning here: The formula metavariable A at index k, used to identify a particular member of a finite formation sequence.
Conventional reading: evaluation function induced by valuation v sub 1
Meaning here: The evaluation function induced by valuation v sub 1; it extends the assignment on sentence letters to every formula.
Conventional reading: open parenthesis open parenthesis not open parenthesis sentence letter p sub 0 implies sentence letter p sub 1 close parenthesis implies open parenthesis sentence letter p sub 0 or sentence letter p sub 1 close parenthesis close parenthesis and not open parenthesis sentence letter p sub 0 and sentence letter p sub 1 close parenthesis close parenthesis
Meaning here: A conjunction whose left conjunct is a conditional from the negated p-zero-to-p-one conditional to the p-zero-or-p-one disjunction, and whose right conjunct negates p zero and p one.
Conventional reading: A sub i is syntactically identical to not A sub j
Meaning here: The statement read 'A sub i is syntactically identical to not A sub j' compares symbol strings for exact syntactic identity, not merely equal truth value or logical equivalence.
Conventional reading: valuation v colon the set of propositional variables maps to open set brace true comma false close set brace
Meaning here: Valuation v is a function from the set of propositional variables to the two-element set containing true and false.
Conventional reading: A is valid
Meaning here: Formula A is valid: every propositional valuation makes A true.
Conventional reading: the result of simultaneous substitution in A using B sub 1 for sentence letter p sub 1 comma and so on comma B sub n for sentence letter p sub n
Meaning here: The expression read 'the result of simultaneous substitution in A using B sub 1 for sentence letter p sub 1 comma and so on comma B sub n for sentence letter p sub n' specifies a substitution of formulas for propositional variables; the spoken order states what is inserted, what it replaces, and where.
Conventional reading: evaluation function induced by valuation v sub 2
Meaning here: The evaluation function induced by valuation v sub 2; it extends the assignment on sentence letters to every formula.
Conventional reading: capital Delta semantically entails A
Meaning here: The statement read 'capital Delta semantically entails A' says that every propositional valuation satisfying all premises on the left also satisfies the conclusion on the right.
Conventional reading: propositional variable p
Meaning here: The propositional variable p, which stands for a sentence or proposition that is either true or false.
Conventional reading: valuation v does not satisfy B
Meaning here: Formula B is false under propositional valuation v.
Conventional reading: open parenthesis A sub j and A sub k close parenthesis
Meaning here: The conjunction of indexed formulas A sub j and A sub k, with its outer parentheses shown.
Conventional reading: open set brace true comma false close set brace
Meaning here: The two-element set of propositional truth values: true and false.
Conventional reading: index n
Meaning here: The final index n of a formation sequence, or the length parameter used in induction on such sequences.
Conventional reading: Gamma semantically entails: if A, then B
Meaning here: Every structure satisfying Gamma satisfies the conditional from A to B.
Conventional reading: not sign
Meaning here: The not sign used as a notation variant for propositional negation; it is distinct from the tilde variant.
Conventional reading: open parenthesis A or B close parenthesis
Meaning here: The disjunction of formulas A and B, with its outer parentheses shown.
Conventional reading: sentence letter p sub i
Meaning here: The expression read 'sentence letter p sub i' is a sentence letter of the propositional language, standing for a proposition that receives one of the two truth values.
Conventional reading: valuation v
Meaning here: The fraktur letter v names a propositional truth-value assignment.
Conventional reading: if A, then B
Meaning here: The conditional whose antecedent is A and whose consequent is B.
Conventional reading: A sub n is syntactically identical to not A sub j
Meaning here: The statement read 'A sub n is syntactically identical to not A sub j' compares symbol strings for exact syntactic identity, not merely equal truth value or logical equivalence.
Conventional reading: the set of formulas of language L sub 0 is a subset of S
Meaning here: Every formula of language L sub 0 belongs to the set S.
Conventional reading: Gamma together with assumption A semantically entails B
Meaning here: Every structure satisfying Gamma and A also satisfies B.
Conventional reading: A sub n is syntactically identical to open parenthesis A sub j or A sub k close parenthesis
Meaning here: The statement read 'A sub n is syntactically identical to open parenthesis A sub j or A sub k close parenthesis' compares symbol strings for exact syntactic identity, not merely equal truth value or logical equivalence.
Conventional reading: negation
Meaning here: The unary logical connective not, used to form a negation.
Conventional reading: open parenthesis sentence letter p sub 0 implies open parenthesis not sentence letter p sub 1 implies not sentence letter p sub 0 close parenthesis close parenthesis
Meaning here: A conditional from sentence letter p sub 0 to the conditional from not p sub 1 to not p sub 0.
Conventional reading: B prime
Meaning here: The primed formula metavariable B prime, used to distinguish a substituted formula from its unprimed counterpart.
Conventional reading: double arrow biconditional symbol
Meaning here: The expression read 'double arrow biconditional symbol' is a notation variant discussed for a propositional connective or syntactic relation; its spoken form names the role rather than relying on the glyph.
Conventional reading: horseshoe conditional symbol
Meaning here: The expression read 'horseshoe conditional symbol' is a notation variant discussed for a propositional connective or syntactic relation; its spoken form names the role rather than relying on the glyph.
Conventional reading: the result of substituting B for sentence letter p sub i in A
Meaning here: The expression read 'the result of substituting B for sentence letter p sub i in A' specifies a substitution of formulas for propositional variables; the spoken order states what is inserted, what it replaces, and where.
Conventional reading: sentence letter p sub 1
Meaning here: The expression read 'sentence letter p sub 1' is a sentence letter of the propositional language, standing for a proposition that receives one of the two truth values.
Conventional reading: indices j and k are less than i
Meaning here: The condition read 'indices j and k are less than i' constrains indices so that cited formulas occur earlier in a finite formation sequence.
Conventional reading: truth value of A under valuation v sub 1 equals truth value of A under valuation v sub 2
Meaning here: The evaluation functions induced by valuations v sub 1 and v sub 2 assign the same truth value to formula A.
Conventional reading: sentence letter p sub 0
Meaning here: The expression read 'sentence letter p sub 0' is a sentence letter of the propositional language, standing for a proposition that receives one of the two truth values.
Conventional reading: A if and only if B
Meaning here: The biconditional with formula A on the left and formula B on the right.
Conventional reading: the empty premise set semantically entails A
Meaning here: Formula A follows semantically from no premises, so A is true under every propositional valuation.
Conventional reading: sequence B sub 0 comma and so on comma B sub n comma C sub 0 comma and so on comma C sub m comma open parenthesis B sub n implies C sub m close parenthesis
Meaning here: The sequence read 'sequence B sub 0 comma and so on comma B sub n comma C sub 0 comma and so on comma C sub m comma open parenthesis B sub n implies C sub m close parenthesis' is a finite formation sequence whose earlier entries justify the construction of its final propositional formula.
Conventional reading: open parenthesis open parenthesis sentence letter p sub 0 or sentence letter p sub 1 close parenthesis and sentence letter p sub 2 close parenthesis
Meaning here: The conjunction of the disjunction of p sub 0 with p sub 1 and the sentence letter p sub 2.
Conventional reading: propositional language L sub 0
Meaning here: The propositional language L sub 0.
Conventional reading: evaluation function induced by valuation v, from formulas of language L sub 0 to the truth values true and false
Meaning here: The evaluation function induced by valuation v maps every formula of language L sub 0 to either true or false.
Conventional reading: sentence letter p sub n
Meaning here: The expression read 'sentence letter p sub n' is a sentence letter of the propositional language, standing for a proposition that receives one of the two truth values.
Conventional reading: the set of propositional variables
Meaning here: The set of all propositional variables, or sentence letters, in the language.
Conventional reading: open parenthesis B binary connective star C close parenthesis
Meaning here: The fully parenthesized result of applying an arbitrary binary connective to formulas B and C.
Conventional reading: sequence A sub 0 comma and so on comma A sub n
Meaning here: The finite sequence from A sub 0 through A sub n; it is a formation sequence only when the definition's formation conditions are satisfied.
Conventional reading: sentence letter p sub n is a member of the set of propositional variables
Meaning here: Sentence letter p sub n is a member of the set of propositional variables.
Conventional reading: A is a member of the set of formulas of language L sub 0
Meaning here: Formula A is a well-formed formula of propositional language L sub 0.
Conventional reading: open parenthesis A implies B close parenthesis and open parenthesis B implies A close parenthesis
Meaning here: The conjunction of the conditional from A to B and the converse conditional from B to A.
Conventional reading: open parenthesis not sentence letter p sub 0 and sentence letter p sub 0 close parenthesis
Meaning here: The contradictory conjunction of not p sub 0 with p sub 0.
Conventional reading: truth constant true
Meaning here: The propositional truth constant true; it is a nullary connective, not a formula built from sentence letters.
Conventional reading: disjunction
Meaning here: The binary logical connective or, used to form a disjunction.
Conventional reading: Truth value clauses. Falsum is false. A sentence letter has the value assigned to it. Not A is true exactly when A is false. A and B is true exactly when both A and B are true. A or B is true exactly when at least one of A and B is true. If A, then B is false exactly when A is true and B is false.
Meaning here: The recursive truth definition for falsum, sentence letters, negation, conjunction, disjunction, and the material conditional under propositional valuation v.
Conventional reading: A sub n is syntactically identical to open parenthesis A sub j implies A sub k close parenthesis
Meaning here: The statement read 'A sub n is syntactically identical to open parenthesis A sub j implies A sub k close parenthesis' compares symbol strings for exact syntactic identity, not merely equal truth value or logical equivalence.
Conventional reading: not open parenthesis open parenthesis sentence letter p sub 0 implies sentence letter p sub 1 close parenthesis and sentence letter p sub 2 close parenthesis
Meaning here: The negation of the conjunction whose conjuncts are the conditional from p sub 0 to p sub 1 and sentence letter p sub 2.
Conventional reading: valuation v satisfies C
Meaning here: Formula C is true under propositional valuation v.
Conventional reading: Gamma, a set of formulas
Meaning here: An arbitrary set Gamma of propositional formulas, used as premises in satisfaction and semantic consequence.
Conventional reading: i is less than or equal to n
Meaning here: The condition read 'i is less than or equal to n' constrains indices so that cited formulas occur earlier in a finite formation sequence.
Conventional reading: k is less than or equal to n
Meaning here: The condition read 'k is less than or equal to n' constrains indices so that cited formulas occur earlier in a finite formation sequence.
Conventional reading: truth value of A under valuation v
Meaning here: The truth value assigned to formula A by the evaluation function induced by valuation v.
Conventional reading: true
Meaning here: The truth value true.
Conventional reading: property P
Meaning here: The property P used in the structural induction principle for propositional formulas.
Conventional reading: Gamma is a subset of capital Delta
Meaning here: Every formula in assumption set Gamma also belongs to assumption set Delta.
Conventional reading: valuation v sub 1
Meaning here: The propositional truth-value assignment named v sub 1.
Conventional reading: tilde negation symbol
Meaning here: The expression read 'tilde negation symbol' is a notation variant discussed for a propositional connective or syntactic relation; its spoken form names the role rather than relying on the glyph.
Conventional reading: the set of formulas of language L sub 0 equals S
Meaning here: The set of all formulas of language L sub 0 is exactly the set S.
Conventional reading: A sub n is syntactically identical to open parenthesis A sub j and A sub k close parenthesis
Meaning here: The statement read 'A sub n is syntactically identical to open parenthesis A sub j and A sub k close parenthesis' compares symbol strings for exact syntactic identity, not merely equal truth value or logical equivalence.
Conventional reading: A sub i
Meaning here: The formula metavariable A at index i, used to identify a particular member of a finite formation sequence.
Conventional reading: valuation v satisfies A
Meaning here: Formula A is true under propositional valuation v.
Conventional reading: valuation v sub 2
Meaning here: The propositional truth-value assignment named v sub 2.
Conventional reading: open parenthesis B prime implies C prime close parenthesis
Meaning here: The conditional from primed formula B to primed formula C, with its outer parentheses shown.
Conventional reading: binary connective star
Meaning here: A metavariable for an arbitrary binary propositional connective.
Conventional reading: the set of formulas of language L sub 0
Meaning here: The set of all well-formed formulas of propositional language L sub 0.
Conventional reading: open parenthesis open parenthesis not sentence letter p sub 0 implies sentence letter p sub 1 close parenthesis and sentence letter p sub 2 close parenthesis
Meaning here: The conjunction of the conditional from not p sub 0 to p sub 1 and sentence letter p sub 2.
Conventional reading: sequence B sub 0 comma and so on comma B sub n comma C sub 0 comma and so on comma C sub m comma open parenthesis B sub n and C sub m close parenthesis
Meaning here: The sequence read 'sequence B sub 0 comma and so on comma B sub n comma C sub 0 comma and so on comma C sub m comma open parenthesis B sub n and C sub m close parenthesis' is a finite formation sequence whose earlier entries justify the construction of its final propositional formula.
Conventional reading: A sub j
Meaning here: The formula metavariable A at index j, used to identify a particular member of a finite formation sequence.
Conventional reading: left right arrow biconditional symbol
Meaning here: The expression read 'left right arrow biconditional symbol' is a notation variant discussed for a propositional connective or syntactic relation; its spoken form names the role rather than relying on the glyph.
Conventional reading: A sub i is syntactically identical to open parenthesis A sub j or A sub k close parenthesis
Meaning here: The statement read 'A sub i is syntactically identical to open parenthesis A sub j or A sub k close parenthesis' compares symbol strings for exact syntactic identity, not merely equal truth value or logical equivalence.
Conventional reading: not open parenthesis sentence letter p sub 1 and sentence letter p sub 0 close parenthesis
Meaning here: The negation of the conjunction of sentence letters p sub 1 and p sub 0.
Conventional reading: A sub i is syntactically identical to open parenthesis A sub j implies A sub k close parenthesis
Meaning here: The statement read 'A sub i is syntactically identical to open parenthesis A sub j implies A sub k close parenthesis' compares symbol strings for exact syntactic identity, not merely equal truth value or logical equivalence.
Conventional reading: formula A
Meaning here: The metavariable A denotes an arbitrary formula.
Conventional reading: the result of substituting B for p in A
Meaning here: The expression read 'the result of substituting B for p in A' specifies a substitution of formulas for propositional variables; the spoken order states what is inserted, what it replaces, and where.
Conventional reading: The truth value of diamond applied to A, B, and C is the truth value of B when A is true, and is the truth value of C when A is false.
Meaning here: A proposed ternary connective that selects its second argument when the first argument is true and its third argument when the first argument is false.
Conventional reading: A is syntactically identical to B
Meaning here: The statement read 'A is syntactically identical to B' compares symbol strings for exact syntactic identity, not merely equal truth value or logical equivalence.
Conventional reading: A is syntactically identical to A sub n
Meaning here: The statement read 'A is syntactically identical to A sub n' compares symbol strings for exact syntactic identity, not merely equal truth value or logical equivalence.
Conventional reading: centered dot conjunction symbol
Meaning here: The expression read 'centered dot conjunction symbol' is a notation variant discussed for a propositional connective or syntactic relation; its spoken form names the role rather than relying on the glyph.
Conventional reading: is syntactically identical to
Meaning here: The statement read 'is syntactically identical to' compares symbol strings for exact syntactic identity, not merely equal truth value or logical equivalence.
Conventional reading: Gamma union capital Delta semantically entails B
Meaning here: The statement read 'Gamma union capital Delta semantically entails B' says that every propositional valuation satisfying all premises on the left also satisfies the conclusion on the right.
Conventional reading: A is syntactically identical to open parenthesis B or C close parenthesis
Meaning here: The statement read 'A is syntactically identical to open parenthesis B or C close parenthesis' compares symbol strings for exact syntactic identity, not merely equal truth value or logical equivalence.
Conventional reading: right arrow conditional symbol
Meaning here: The expression read 'right arrow conditional symbol' is a notation variant discussed for a propositional connective or syntactic relation; its spoken form names the role rather than relying on the glyph.
Conventional reading: capital Delta union open set brace A close set brace semantically entails B
Meaning here: The statement read 'capital Delta union open set brace A close set brace semantically entails B' says that every propositional valuation satisfying all premises on the left also satisfies the conclusion on the right.
Conventional reading: valuation v satisfies every formula in Gamma
Meaning here: Every formula in the assumption set Gamma is true under propositional valuation v.
Conventional reading: set S
Meaning here: The class S of formulas having the property used in the structural induction argument.
Conventional reading: ampersand conjunction symbol
Meaning here: The expression read 'ampersand conjunction symbol' is a notation variant discussed for a propositional connective or syntactic relation; its spoken form names the role rather than relying on the glyph.
Conventional reading: sequence C sub 0 comma and so on comma C sub m
Meaning here: The sequence read 'sequence C sub 0 comma and so on comma C sub m' is a finite formation sequence whose earlier entries justify the construction of its final propositional formula.
Conventional reading: valuation v satisfies the current induction-case formula
Meaning here: A context-sensitive satisfaction statement whose current induction-case formula is expanded in each occurrence.
Conventional reading: open parenthesis B implies C close parenthesis
Meaning here: The conditional from formula B to formula C, with its outer parentheses shown.
Conventional reading: Gamma semantically entails B
Meaning here: The statement read 'Gamma semantically entails B' says that every propositional valuation satisfying all premises on the left also satisfies the conclusion on the right.
Conventional reading: sequence A
Meaning here: The sequence read 'sequence A' is a finite formation sequence whose earlier entries justify the construction of its final propositional formula.
Conventional reading: A is syntactically identical to open parenthesis A sub j and A sub k close parenthesis
Meaning here: The statement read 'A is syntactically identical to open parenthesis A sub j and A sub k close parenthesis' compares symbol strings for exact syntactic identity, not merely equal truth value or logical equivalence.
Conventional reading: formula C
Meaning here: The metavariable C denotes an arbitrary formula.
Conventional reading: Gamma union the singleton set containing not A
Meaning here: The assumption set obtained by adding the negated formula not A to Gamma.
Conventional reading: B binary connective star C
Meaning here: The result of applying an arbitrary binary connective to formulas B and C without outer parentheses.
Conventional reading: open parenthesis not sentence letter p sub 0 and sentence letter p sub 1 close parenthesis
Meaning here: The conjunction of not p sub 0 with sentence letter p sub 1.
Conventional reading: truth value of A under valuation v equals true
Meaning here: Formula A has truth value true under the evaluation function induced by valuation v.
Conventional reading: open parenthesis sentence letter p sub 0 if and only if sentence letter p sub 1 close parenthesis implies open parenthesis sentence letter p sub 2 if and only if not sentence letter p sub 1 close parenthesis
Meaning here: A conditional from the biconditional between p sub 0 and p sub 1 to the biconditional between p sub 2 and not p sub 1.
Conventional reading: Gamma semantically entails A
Meaning here: Every structure that satisfies all assumptions in Gamma also satisfies formula A.
Conventional reading: valuation v satisfies B
Meaning here: Formula B is true under propositional valuation v.
Conventional reading: sequence A sub 0 comma and so on comma A sub j
Meaning here: The sequence read 'sequence A sub 0 comma and so on comma A sub j' is a finite formation sequence whose earlier entries justify the construction of its final propositional formula.
Conventional reading: double right arrow conditional symbol
Meaning here: The expression read 'double right arrow conditional symbol' is a notation variant discussed for a propositional connective or syntactic relation; its spoken form names the role rather than relying on the glyph.
Conventional reading: indices j and k are less than n
Meaning here: The condition read 'indices j and k are less than n' constrains indices so that cited formulas occur earlier in a finite formation sequence.
Conventional reading: B sub n
Meaning here: The formula metavariable B at index n, used to identify a particular member of a finite formation sequence.
Conventional reading: A sub n is a member of the set of formulas of language L sub 0
Meaning here: The indexed string A sub n is a well-formed formula of language L sub 0.
Conventional reading: if and only if
Meaning here: The binary biconditional connective, read if and only if.
Conventional reading: A or B
Meaning here: The disjunction of formulas A and B.
Conventional reading: sequence B sub 0 comma and so on comma B sub n comma not B sub n
Meaning here: The sequence read 'sequence B sub 0 comma and so on comma B sub n comma not B sub n' is a finite formation sequence whose earlier entries justify the construction of its final propositional formula.
Conventional reading: valuation v does not satisfy the current induction-case formula
Meaning here: A context-sensitive non-satisfaction statement whose current induction-case formula is expanded in this occurrence.
Conventional reading: sequence sentence letter p sub 0 comma sentence letter p sub 1 comma sentence letter p sub 0 comma open parenthesis sentence letter p sub 1 and sentence letter p sub 0 close parenthesis comma open parenthesis sentence letter p sub 0 implies sentence letter p sub 1 close parenthesis comma not open parenthesis sentence letter p sub 1 and sentence letter p sub 0 close parenthesis
Meaning here: The sequence read 'sequence sentence letter p sub 0 comma sentence letter p sub 1 comma sentence letter p sub 0 comma open parenthesis sentence letter p sub 1 and sentence letter p sub 0 close parenthesis comma open parenthesis sentence letter p sub 0 implies sentence letter p sub 1 close parenthesis comma not open parenthesis sentence letter p sub 1 and sentence letter p sub 0 close parenthesis' is a finite formation sequence whose earlier entries justify the construction of its final propositional formula.
Conventional reading: sequence A sub 0 comma and so on comma A sub k
Meaning here: The sequence read 'sequence A sub 0 comma and so on comma A sub k' is a finite formation sequence whose earlier entries justify the construction of its final propositional formula.
Conventional reading: S is a subset of the set of formulas of language L sub 0
Meaning here: Every member of S is a well-formed formula of language L sub 0.
Conventional reading: A is a member of Gamma
Meaning here: Formula A belongs to the assumption set Gamma.
Conventional reading: ternary connective diamond
Meaning here: A proposed ternary propositional connective represented by a diamond.
Conventional reading: open parenthesis open parenthesis sentence letter p sub 0 if and only if open parenthesis not sentence letter p sub 1 and sentence letter p sub 2 close parenthesis close parenthesis or open parenthesis sentence letter p sub 2 implies open parenthesis sentence letter p sub 0 if and only if sentence letter p sub 1 close parenthesis close parenthesis close parenthesis
Meaning here: A disjunction whose left disjunct is the biconditional between p sub 0 and the conjunction of not p sub 1 with p sub 2, and whose right disjunct is a conditional from p sub 2 to the biconditional between p sub 0 and p sub 1.
Conventional reading: A and B
Meaning here: The conjunction of formulas A and B.
Conventional reading: open parenthesis B or C close parenthesis
Meaning here: The disjunction of formulas B and C, with its outer parentheses shown.
Conventional reading: sequence B sub 0 comma and so on comma B sub n comma C sub 0 comma and so on comma C sub m comma open parenthesis B sub n or C sub m close parenthesis
Meaning here: The sequence read 'sequence B sub 0 comma and so on comma B sub n comma C sub 0 comma and so on comma C sub m comma open parenthesis B sub n or C sub m close parenthesis' is a finite formation sequence whose earlier entries justify the construction of its final propositional formula.
Conventional reading: not falsum
Meaning here: The negation of falsum.
Conventional reading: open parenthesis open parenthesis sentence letter p sub 0 and not sentence letter p sub 1 close parenthesis implies open parenthesis not sentence letter p sub 0 and sentence letter p sub 2 close parenthesis close parenthesis if and only if open parenthesis open parenthesis sentence letter p sub 2 implies sentence letter p sub 0 close parenthesis implies open parenthesis sentence letter p sub 0 implies sentence letter p sub 1 close parenthesis close parenthesis
Meaning here: A biconditional between a conditional from p-zero-and-not-p-one to not-p-zero-and-p-two, and a nested conditional from p-two-implies-p-zero to p-zero-implies-p-one.
Conventional reading: m is less than n
Meaning here: The condition read 'm is less than n' constrains indices so that cited formulas occur earlier in a finite formation sequence.
Conventional reading: A is syntactically identical to open parenthesis B and C close parenthesis
Meaning here: The statement read 'A is syntactically identical to open parenthesis B and C close parenthesis' compares symbol strings for exact syntactic identity, not merely equal truth value or logical equivalence.
Conventional reading: not A
Meaning here: The negation of formula A.
Conventional reading: sequence B sub 0 comma and so on comma B sub n
Meaning here: The sequence read 'sequence B sub 0 comma and so on comma B sub n' is a finite formation sequence whose earlier entries justify the construction of its final propositional formula.
Conventional reading: wedge conjunction symbol
Meaning here: The expression read 'wedge conjunction symbol' is a notation variant discussed for a propositional connective or syntactic relation; its spoken form names the role rather than relying on the glyph.
Conventional reading: a contradiction
Meaning here: The falsum symbol, meaning contradiction.
Conventional reading: open parenthesis A implies B close parenthesis
Meaning here: The conditional from formula A to formula B, with its outer parentheses shown.
Conventional reading: conditional
Meaning here: The binary conditional connective, read as if the antecedent then the consequent.
Conventional reading: formula B
Meaning here: The metavariable B denotes an arbitrary formula.
Conventional reading: propositional language L sub 0
Meaning here: The propositional language L sub 0.
Conventional reading: sequence sentence letter p sub 0 comma sentence letter p sub 1 comma open parenthesis sentence letter p sub 1 and sentence letter p sub 0 close parenthesis comma not open parenthesis sentence letter p sub 1 and sentence letter p sub 0 close parenthesis
Meaning here: The sequence read 'sequence sentence letter p sub 0 comma sentence letter p sub 1 comma open parenthesis sentence letter p sub 1 and sentence letter p sub 0 close parenthesis comma not open parenthesis sentence letter p sub 1 and sentence letter p sub 0 close parenthesis' is a finite formation sequence whose earlier entries justify the construction of its final propositional formula.
Conventional reading: A sub n
Meaning here: The formula metavariable A at index n, used to identify a particular member of a finite formation sequence.
Conventional reading: A sub i is syntactically identical to open parenthesis A sub j and A sub k close parenthesis
Meaning here: The statement read 'A sub i is syntactically identical to open parenthesis A sub j and A sub k close parenthesis' compares symbol strings for exact syntactic identity, not merely equal truth value or logical equivalence.
Conventional reading: not B
Meaning here: The negation of formula B.
Conventional reading: triple bar biconditional symbol
Meaning here: The triple-bar symbol as a notation variant for the material biconditional in the source's notation comparison.
Conventional reading: the set of formulas of language L sub 0 is a subset of F
Meaning here: Every formula of language L sub 0 belongs to the set F of strings having formation sequences.
Conventional reading: C prime
Meaning here: The primed formula metavariable C prime, used to distinguish a substituted formula from its unprimed counterpart.
Conventional reading: open parenthesis B and C close parenthesis
Meaning here: The conjunction of formulas B and C, with its outer parentheses shown.
Conventional reading: A is syntactically identical to not B
Meaning here: The statement read 'A is syntactically identical to not B' compares symbol strings for exact syntactic identity, not merely equal truth value or logical equivalence.
Conventional reading: set F
Meaning here: The set F of symbol strings that possess a formation sequence.
Conventional reading: A is syntactically identical to open parenthesis B implies C close parenthesis
Meaning here: The statement read 'A is syntactically identical to open parenthesis B implies C close parenthesis' compares symbol strings for exact syntactic identity, not merely equal truth value or logical equivalence.
Conventional reading: false
Meaning here: The truth value false.
Conventional reading: valuation v sub 1 applied to sentence letter p sub n equals valuation v sub 2 applied to sentence letter p sub n
Meaning here: Valuations v sub 1 and v sub 2 assign the same truth value to sentence letter p sub n.
Conventional reading: valuation v applied to sentence letter p sub i equals true
Meaning here: Valuation v assigns truth value true to sentence letter p sub i.
Conventional reading: valuation v does not satisfy A
Meaning here: Formula A is false under propositional valuation v.
Conventional reading: B sub 1
Meaning here: The formula metavariable B at index 1, used to identify a particular member of a finite formation sequence.
Conventional reading: open parenthesis A and B close parenthesis
Meaning here: The conjunction of formulas A and B, with its outer parentheses shown.
| A | not A |
|---|---|
| True | False |
| False | True |
Words-only linearization: Negation truth table. Row one. A is true. Not A is false. Row two. A is false. Not A is true.
| A | B | A and B |
|---|---|---|
| True | True | True |
| True | False | False |
| False | True | False |
| False | False | False |
Words-only linearization: Conjunction truth table. Row one. A is true. B is true. A and B is true. Row two. A is true. B is false. A and B is false. Row three. A is false. B is true. A and B is false. Row four. A is false. B is false. A and B is false.
| A | B | A or B |
|---|---|---|
| True | True | True |
| True | False | True |
| False | True | True |
| False | False | False |
Words-only linearization: Disjunction truth table. Row one. A is true. B is true. A or B is true. Row two. A is true. B is false. A or B is true. Row three. A is false. B is true. A or B is true. Row four. A is false. B is false. A or B is false.
| A | B | if A then B |
|---|---|---|
| True | True | True |
| True | False | False |
| False | True | True |
| False | False | True |
Words-only linearization: Material conditional truth table. Row one. A is true. B is true. If A, then B is true. Row two. A is true. B is false. If A, then B is false. Row three. A is false. B is true. If A, then B is true. Row four. A is false. B is false. If A, then B is true.
Read as: capital M
Read as: vee