# Measurable projection theorem

Hi ;

i have this theorem from the book :Set-valued analysis

Let $(\Omega,\mathcal{A},\mu)$ be a complete $\sigma$-finite measure space , $X$ a complete separable metric space and $G\in\mathcal{A}\times > \mathcal{B}(X)$ . Then it's projection $pr_{\Omega}(G)=\lbrace t\in \Omega > ,\exists x\in X, (t,x)\in G\rbrace \in > \mathcal{A}$

there is a prove of this in the book of Castaing "convexe and measurable multifunction" in chapter 3 but i dont understand it