let C be non empty set ; :: thesis: for f, g being Membership_Func of C holds min f,g = (C,f @ ) "/\" (C,g @ )
let f, g be Membership_Func of C; :: thesis: min f,g = (C,f @ ) "/\" (C,g @ )
A1:
(RealPoset [.0 ,1.]) |^ C = product (C --> (RealPoset [.0 ,1.]))
by YELLOW_1:def 5;
set fg = (C,f @ ) "/\" (C,g @ );
set R = RealPoset [.0 ,1.];
set J = C --> (RealPoset [.0 ,1.]);
now let c be
Element of
C;
:: thesis: (@ ((C,f @ ) "/\" (C,g @ ))) . c = min (f . c),(g . c)A2:
for
c being
Element of
C holds
(C --> (RealPoset [.0 ,1.])) . c is
Semilattice
by FUNCOP_1:13;
(C --> (RealPoset [.0 ,1.])) . c = RealPoset [.0 ,1.]
by FUNCOP_1:13;
hence (@ ((C,f @ ) "/\" (C,g @ ))) . c =
((C,f @ ) . c) "/\" ((C,g @ ) . c)
by A1, A2, Th11
.=
min (f . c),
(g . c)
;
:: thesis: verum end;
hence
min f,g = (C,f @ ) "/\" (C,g @ )
by FUZZY_1:def 4; :: thesis: verum