let A be non empty set ; 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); (maxfuncreal A) . (f,((minfuncreal A) . (f,g))) = f
now for x being Element of A holds ((maxfuncreal A) . (f,((minfuncreal A) . (f,g)))) . x = f . xlet x be
Element of
A;
((maxfuncreal A) . (f,((minfuncreal A) . (f,g)))) . x = f . xA1:
x in dom (minreal .: (f,g))
by Lm6;
A2:
x in dom (maxreal .: (f,(minreal .: (f,g))))
by Lm6;
thus ((maxfuncreal A) . (f,((minfuncreal A) . (f,g)))) . x =
((maxfuncreal A) . (f,(minreal .: (f,g)))) . x
by Def5
.=
(maxreal .: (f,(minreal .: (f,g)))) . x
by Def4
.=
maxreal . (
(f . x),
((minreal .: (f,g)) . x))
by A2, FUNCOP_1:22
.=
maxreal . (
(f . x),
(minreal . ((f . x),(g . x))))
by A1, FUNCOP_1:22
.=
f . x
by Th5
;
verum end;
hence
(maxfuncreal A) . (f,((minfuncreal A) . (f,g))) = f
by FUNCT_2:63; verum