let D, D9, E be non empty set ; for d1, d2 being Element of D
for d9 being Element of D9
for F being Function of [:D,D9:],E
for p being FinSequence of D st p = <*d1,d2*> holds
F [:] p,d9 = <*(F . d1,d9),(F . d2,d9)*>
let d1, d2 be Element of D; for d9 being Element of D9
for F being Function of [:D,D9:],E
for p being FinSequence of D st p = <*d1,d2*> holds
F [:] p,d9 = <*(F . d1,d9),(F . d2,d9)*>
let d9 be Element of D9; for F being Function of [:D,D9:],E
for p being FinSequence of D st p = <*d1,d2*> holds
F [:] p,d9 = <*(F . d1,d9),(F . d2,d9)*>
let F be Function of [:D,D9:],E; for p being FinSequence of D st p = <*d1,d2*> holds
F [:] p,d9 = <*(F . d1,d9),(F . d2,d9)*>
let p be FinSequence of D; ( p = <*d1,d2*> implies F [:] p,d9 = <*(F . d1,d9),(F . d2,d9)*> )
assume A1:
p = <*d1,d2*>
; F [:] p,d9 = <*(F . d1,d9),(F . d2,d9)*>
A2:
p . 2 = d2
by A1, FINSEQ_1:61;
reconsider r = F [:] p,d9 as FinSequence of E by Th97;
len p = 2
by A1, FINSEQ_1:61;
then A3:
len r = 2
by Th98;
then
2 in Seg (len r)
;
then
2 in dom r
by FINSEQ_1:def 3;
then A4:
r . 2 = F . d2,d9
by A2, FUNCOP_1:35;
1 in Seg (len r)
by A3;
then A5:
1 in dom r
by FINSEQ_1:def 3;
p . 1 = d1
by A1, FINSEQ_1:61;
then
r . 1 = F . d1,d9
by A5, FUNCOP_1:35;
hence
F [:] p,d9 = <*(F . d1,d9),(F . d2,d9)*>
by A3, A4, FINSEQ_1:61; verum