let A be non empty set ; for f, g being Element of Funcs A,REAL holds (minfuncreal A) . f,g = (minfuncreal A) . g,f
let f, g be Element of Funcs A,REAL ; (minfuncreal A) . f,g = (minfuncreal A) . g,f
now let x be
Element of
A;
((minfuncreal A) . f,g) . x = ((minfuncreal A) . g,f) . xA1:
x in dom (minreal .: f,g)
by Lm8;
A2:
x in dom (minreal .: g,f)
by Lm8;
thus ((minfuncreal A) . f,g) . x =
(minreal .: f,g) . x
by Def6
.=
minreal . (f . x),
(g . x)
by A1, FUNCOP_1:28
.=
minreal . (g . x),
(f . x)
by Th9
.=
(minreal .: g,f) . x
by A2, FUNCOP_1:28
.=
((minfuncreal A) . g,f) . x
by Def6
;
verum end;
hence
(minfuncreal A) . f,g = (minfuncreal A) . g,f
by FUNCT_2:113; verum