let C1 be non empty set ; for f being RMembership_Func of C1,C1 holds f (#) (Zmf C1,C1) = (Zmf C1,C1) (#) f
let f be RMembership_Func of C1,C1; f (#) (Zmf C1,C1) = (Zmf C1,C1) (#) f
f (#) (Zmf C1,C1) = Zmf C1,C1
by Th23;
hence
f (#) (Zmf C1,C1) = (Zmf C1,C1) (#) f
by Th22; verum