let A be non empty set ; :: thesis: for f, g being Element of Funcs A,REAL holds (maxfuncreal A) . f,((minfuncreal A) . f,g) = f
let f, g be Element of Funcs A,REAL ; :: thesis: (maxfuncreal A) . f,((minfuncreal A) . f,g) = f
now let x be
Element of
A;
:: thesis: ((maxfuncreal A) . f,((minfuncreal A) . f,g)) . x = f . xA1:
x in dom (minreal .: f,g)
by Lm8;
A2:
x in dom (maxreal .: f,(minreal .: f,g))
by Lm8;
thus ((maxfuncreal A) . f,((minfuncreal A) . f,g)) . x =
((maxfuncreal A) . f,(minreal .: f,g)) . x
by Def6
.=
(maxreal .: f,(minreal .: f,g)) . x
by Def5
.=
maxreal . (f . x),
((minreal .: f,g) . x)
by A2, FUNCOP_1:28
.=
maxreal . (f . x),
(minreal . (f . x),(g . x))
by A1, FUNCOP_1:28
.=
f . x
by Th12
;
:: thesis: verum end;
hence
(maxfuncreal A) . f,((minfuncreal A) . f,g) = f
by FUNCT_2:113; :: thesis: verum