let N be Nat; for V being set
for loc being b1 -valued Function st loc | (Seg N) is one-to-one & Seg N c= dom loc holds
for i, j being Nat st 1 <= i & i <= N & 1 <= j & j <= N & i <> j holds
loc /. i <> loc /. j
let V be set ; for loc being V -valued Function st loc | (Seg N) is one-to-one & Seg N c= dom loc holds
for i, j being Nat st 1 <= i & i <= N & 1 <= j & j <= N & i <> j holds
loc /. i <> loc /. j
let loc be V -valued Function; ( loc | (Seg N) is one-to-one & Seg N c= dom loc implies for i, j being Nat st 1 <= i & i <= N & 1 <= j & j <= N & i <> j holds
loc /. i <> loc /. j )
set f = loc | (Seg N);
assume that
A1:
loc | (Seg N) is one-to-one
and
A2:
Seg N c= dom loc
; for i, j being Nat st 1 <= i & i <= N & 1 <= j & j <= N & i <> j holds
loc /. i <> loc /. j
let i, j be Nat; ( 1 <= i & i <= N & 1 <= j & j <= N & i <> j implies loc /. i <> loc /. j )
assume that
A3:
( 1 <= i & i <= N )
and
A4:
( 1 <= j & j <= N )
and
A5:
i <> j
; loc /. i <> loc /. j
A6:
i in Seg N
by A3, FINSEQ_1:1;
then A7:
i in dom (loc | (Seg N))
by A2, RELAT_1:57;
A8:
j in Seg N
by A4, FINSEQ_1:1;
then A9:
j in dom (loc | (Seg N))
by A2, RELAT_1:57;
A10:
loc /. i = loc . i
by A2, A6, PARTFUN1:def 6;
A11:
(loc | (Seg N)) . i = loc . i
by A7, FUNCT_1:47;
(loc | (Seg N)) . j = loc . j
by A9, FUNCT_1:47;
hence
loc /. i <> loc /. j
by A1, A5, A7, A9, A10, A2, A8, A11, FUNCT_1:def 4, PARTFUN1:def 6; verum