let D, C be non empty finite set ; for F being PartFunc of D,REAL
for A being RearrangmentGen of C st F is total & card C = card D holds
len (MIM (FinS F,D)) = len (CHI A,C)
let F be PartFunc of D,REAL ; for A being RearrangmentGen of C st F is total & card C = card D holds
len (MIM (FinS F,D)) = len (CHI A,C)
let A be RearrangmentGen of C; ( F is total & card C = card D implies len (MIM (FinS F,D)) = len (CHI A,C) )
assume that
A1:
F is total
and
A2:
card C = card D
; len (MIM (FinS F,D)) = len (CHI A,C)
set a = FinS F,D;
reconsider a9 = FinS F,D as finite Function ;
A3:
dom F = D
by A1, PARTFUN1:def 4;
then reconsider F9 = F as finite Function by FINSET_1:29;
reconsider da9 = dom a9, dF9 = dom F9 as finite set ;
A4:
F | D = F
by A3, RELAT_1:97;
D =
(dom F) /\ D
by A3
.=
dom (F | D)
by RELAT_1:90
;
then
F, FinS F,D are_fiberwise_equipotent
by A4, RFUNCT_3:def 14;
then A5:
( dom (FinS F,D) = Seg (len (FinS F,D)) & card da9 = card dF9 )
by CLASSES1:89, FINSEQ_1:def 3;
thus len (CHI A,C) =
len A
by RFUNCT_3:def 6
.=
card C
by Th1
.=
len (FinS F,D)
by A2, A3, A5, FINSEQ_1:78
.=
len (MIM (FinS F,D))
by RFINSEQ:def 3
; verum