$A$ is a set and so is $B$.
$f$ is a function $A \to B$.
I have a math question that asks about $|f(A)|$. What does the notation $|\cdot |$ mean?
$A$ is a set and so is $B$.
$f$ is a function $A \to B$.
I have a math question that asks about $|f(A)|$. What does the notation $|\cdot |$ mean?