let G be ext-real-membered set ; :: thesis: for f, g being ExtReal st g in G holds
f * g in f ** G
let f, g be ExtReal; :: thesis: ( g in G implies f * g in f ** G )
f in {f} by TARSKI:def 1;
hence ( g in G implies f * g in f ** G ) by Th79; :: thesis: verum