let F be ext-real-membered set ; :: thesis: for f being ExtReal
for e being set st e in f /// F holds
ex w being Element of ExtREAL st
( e = f / w & w in F )

let f be ExtReal; :: thesis: for e being set st e in f /// F holds
ex w being Element of ExtREAL st
( e = f / w & w in F )

let e be set ; :: thesis: ( e in f /// F implies ex w being Element of ExtREAL st
( e = f / w & w in F ) )

f /// F = { (f / w) where w is Element of ExtREAL : w in F } by Th211;
hence ( e in f /// F implies ex w being Element of ExtREAL st
( e = f / w & w in F ) ) ; :: thesis: verum