Let $f:\mathbb R^d\longrightarrow\mathbb R$ measurable and $E\subset \mathbb R^d$ measurable, does $f(E)$ measurable ?
I proved that if $f$ is a bijection, it hold since if $g$ is the reciprocal of $f$, then $g$ is mesurable and $f(E)=g^{-1}(E)$, therefore $f(E)$ is measurable.