let G be ext-real-membered set ; :: thesis: for f, g being ExtReal st g in G holds
g / f in G /// f
let f, g be ExtReal; :: thesis: ( g in G implies g / f in G /// f )
f in {f} by TARSKI:def 1;
hence ( g in G implies g / f in G /// f ) by Th102; :: thesis: verum