Misalkan \((X,\tau_X)=(\{1,2,3,4\}, \{\emptyset,\{1\},\{2\},\{1,2\},\{3,4\},X\})\) dan \((Y,\tau_Y)=(\{a,b,c\}, \{\emptyset,\{a\},\{a,c\},Y\})\text{.}\) Definisikan \(f:X\to Y\) melalui \(f(1)=a\text{,}\) \(f(2)=c\text{,}\) dan \(f(3)=f(4)=b\text{.}\) Tunjukkan bahwa \(f\) kontinu.