let C be non empty set ; for f, h, g being Membership_Func of C st h c= & h c= holds
h c=
let f, h, g be Membership_Func of C; ( h c= & h c= implies h c= )
assume A1:
( h c= & h c= )
; h c=
let x be Element of C; FUZZY_1:def 3 (max f,g) . x <= h . x
A2:
max (f . x),(g . x) = (max f,g) . x
by Def5;
( f . x <= h . x & g . x <= h . x )
by A1, Def3;
hence
(max f,g) . x <= h . x
by A2, XXREAL_0:28; verum