Solution
= Solution
A <function> $f:X\to Y$ is \b[<surjective>] if every element of its <codomain> has a <preimage>: for every $y\in Y$, there is some $x\in X$ such that $f(x)=y$.
= Solution
A <function> $f:X\to Y$ is \b[<surjective>] if every element of its <codomain> has a <preimage>: for every $y\in Y$, there is some $x\in X$ such that $f(x)=y$.