let A be non empty set ; :: thesis: for f, g being Element of Funcs A,REAL holds (maxfuncreal A) . f,g = (maxfuncreal A) . g,f
let f, g be Element of Funcs A,REAL ; :: thesis: (maxfuncreal A) . f,g = (maxfuncreal A) . g,f
now let x be
Element of
A;
:: thesis: ((maxfuncreal A) . f,g) . x = ((maxfuncreal A) . g,f) . xA1:
x in dom (maxreal .: f,g)
by Lm8;
A2:
x in dom (maxreal .: g,f)
by Lm8;
thus ((maxfuncreal A) . f,g) . x =
(maxreal .: f,g) . x
by Def5
.=
maxreal . (f . x),
(g . x)
by A1, FUNCOP_1:28
.=
maxreal . (g . x),
(f . x)
by Th8
.=
(maxreal .: g,f) . x
by A2, FUNCOP_1:28
.=
((maxfuncreal A) . g,f) . x
by Def5
;
:: thesis: verum end;
hence
(maxfuncreal A) . f,g = (maxfuncreal A) . g,f
by FUNCT_2:113; :: thesis: verum