I am trying to solve the following question.
Let $f:A \to B$ and $g:A \to B$ be functions. Prove that if $f \subset g$, then $f=g$.
Here is my attempt.
Assume that $f \subset g$. Then, if $(x,y) \in f$, then $(x,y) \in g$. What we have to show is that for every ordered pair $(x,y) \in f$, it is also in $g$ as well and vice versa. and... I'm stuck here. Can anyone give me some help?
Thank you in advance.