$f(S \cap T) \neq f(S) \cap f(T)$
but
$f^{-1}(S \cap T)$ = $f^{-1}(S) \cap f^{-1}(T) $
where $f^{-1}$ is a preimage
what is a preimage and what difference does it make?
$f(S \cap T) \neq f(S) \cap f(T)$
but
$f^{-1}(S \cap T)$ = $f^{-1}(S) \cap f^{-1}(T) $
where $f^{-1}$ is a preimage
what is a preimage and what difference does it make?