let D be non empty set ; for f being FinSequence of D
for p being Element of D
for i being Nat st 1 <= i & i <= len f holds
(Replace f,i,p) /. i = p
let f be FinSequence of D; for p being Element of D
for i being Nat st 1 <= i & i <= len f holds
(Replace f,i,p) /. i = p
let p be Element of D; for i being Nat st 1 <= i & i <= len f holds
(Replace f,i,p) /. i = p
let i be Nat; ( 1 <= i & i <= len f implies (Replace f,i,p) /. i = p )
assume that
A1:
1 <= i
and
A2:
i <= len f
; (Replace f,i,p) /. i = p
i <= len (Replace f,i,p)
by A2, Th7;
then
i in dom (Replace f,i,p)
by A1, FINSEQ_3:27;
then
(Replace f,i,p) /. i = (Replace f,i,p) . i
by PARTFUN1:def 8;
hence
(Replace f,i,p) /. i = p
by A1, A2, Lm2; verum