let C be non empty set ; for f, h, g being Membership_Func of C holds f * (max (g,h)) = max ((f * g),(f * h))
let f, h, g be Membership_Func of C; f * (max (g,h)) = max ((f * g),(f * h))
A1:
C = dom (max ((f * g),(f * h)))
by FUNCT_2:def 1;
A2:
for c being Element of C st c in C holds
(f * (max (g,h))) . c = (max ((f * g),(f * h))) . c
proof
let c be
Element of
C;
( c in C implies (f * (max (g,h))) . c = (max ((f * g),(f * h))) . c )
(f * (max (g,h))) . c =
(f . c) * ((max (g,h)) . c)
by Def2
.=
(f . c) * (max ((g . c),(h . c)))
by FUZZY_1:5
.=
max (
((f . c) * (g . c)),
((f . c) * (h . c)))
by Lm2, Th1
.=
max (
((f * g) . c),
((f . c) * (h . c)))
by Def2
.=
max (
((f * g) . c),
((f * h) . c))
by Def2
;
hence
(
c in C implies
(f * (max (g,h))) . c = (max ((f * g),(f * h))) . c )
by FUZZY_1:5;
verum
end;
C = dom (f * (max (g,h)))
by FUNCT_2:def 1;
hence
f * (max (g,h)) = max ((f * g),(f * h))
by A1, A2, PARTFUN1:5; verum