let v1, v2 be Element of V; :: thesis: ( ex F being FinSequence of the carrier of V st
( F is one-to-one & rng F = Carrier L & v1 = Sum (L (#) F) ) & ex F being FinSequence of the carrier of V st
( F is one-to-one & rng F = Carrier L & v2 = Sum (L (#) F) ) implies v1 = v2 )

given F1 being FinSequence of the carrier of V such that A4: F1 is one-to-one and
A5: rng F1 = Carrier L and
A6: v1 = Sum (L (#) F1) ; :: thesis: ( for F being FinSequence of the carrier of V holds
( not F is one-to-one or not rng F = Carrier L or not v2 = Sum (L (#) F) ) or v1 = v2 )

given F2 being FinSequence of the carrier of V such that A7: F2 is one-to-one and
A8: rng F2 = Carrier L and
A9: v2 = Sum (L (#) F2) ; :: thesis: v1 = v2
defpred S1[ set , set ] means {$2} = F1 " {(F2 . $1)};
A10: len F1 = len F2 by A4, A5, A7, A8, FINSEQ_1:65;
A11: dom F1 = Seg (len F1) by FINSEQ_1:def 3;
A12: dom F2 = Seg (len F2) by FINSEQ_1:def 3;
A13: for x being set st x in dom F1 holds
ex y being set st
( y in dom F1 & S1[x,y] )
proof
let x be set ; :: thesis: ( x in dom F1 implies ex y being set st
( y in dom F1 & S1[x,y] ) )

assume x in dom F1 ; :: thesis: ex y being set st
( y in dom F1 & S1[x,y] )

then F2 . x in rng F1 by A5, A8, A10, A11, A12, FUNCT_1:def 5;
then consider y being set such that
A14: F1 " {(F2 . x)} = {y} by A4, FUNCT_1:144;
take y ; :: thesis: ( y in dom F1 & S1[x,y] )
y in F1 " {(F2 . x)} by A14, TARSKI:def 1;
hence y in dom F1 by FUNCT_1:def 13; :: thesis: S1[x,y]
thus S1[x,y] by A14; :: thesis: verum
end;
consider f being Function of (dom F1),(dom F1) such that
A15: for x being set st x in dom F1 holds
S1[x,f . x] from FUNCT_2:sch 1(A13);
A16: rng f = dom F1
proof
thus rng f c= dom F1 by RELAT_1:def 19; :: according to XBOOLE_0:def 10 :: thesis: dom F1 c= rng f
let y be set ; :: according to TARSKI:def 3 :: thesis: ( not y in dom F1 or y in rng f )
assume A17: y in dom F1 ; :: thesis: y in rng f
then F1 . y in rng F2 by A5, A8, FUNCT_1:def 5;
then consider x being set such that
A18: x in dom F2 and
A19: F2 . x = F1 . y by FUNCT_1:def 5;
F1 " {(F2 . x)} = F1 " (Im (F1,y)) by A17, A19, FUNCT_1:117;
then F1 " {(F2 . x)} c= {y} by A4, FUNCT_1:152;
then {(f . x)} c= {y} by A10, A11, A12, A15, A18;
then A20: f . x = y by ZFMISC_1:24;
x in dom f by A10, A11, A12, A18, FUNCT_2:def 1;
hence y in rng f by A20, FUNCT_1:def 5; :: thesis: verum
end;
set G1 = L (#) F1;
A21: len (L (#) F1) = len F1 by Def8;
A22: ( dom F1 = {} implies dom F1 = {} ) ;
A23: f is one-to-one
proof
let y1 be set ; :: according to FUNCT_1:def 8 :: thesis: for b1 being set holds
( not y1 in proj1 f or not b1 in proj1 f or not f . y1 = f . b1 or y1 = b1 )

let y2 be set ; :: thesis: ( not y1 in proj1 f or not y2 in proj1 f or not f . y1 = f . y2 or y1 = y2 )
assume that
A24: y1 in dom f and
A25: y2 in dom f and
A26: f . y1 = f . y2 ; :: thesis: y1 = y2
A27: y2 in dom F1 by A22, A25, FUNCT_2:def 1;
then A28: F1 " {(F2 . y2)} = {(f . y2)} by A15;
A29: y1 in dom F1 by A22, A24, FUNCT_2:def 1;
then F2 . y1 in rng F1 by A5, A8, A10, A11, A12, FUNCT_1:def 5;
then A30: {(F2 . y1)} c= rng F1 by ZFMISC_1:37;
F2 . y2 in rng F1 by A5, A8, A10, A11, A12, A27, FUNCT_1:def 5;
then A31: {(F2 . y2)} c= rng F1 by ZFMISC_1:37;
F1 " {(F2 . y1)} = {(f . y1)} by A15, A29;
then {(F2 . y1)} = {(F2 . y2)} by A26, A28, A30, A31, FUNCT_1:161;
then A32: F2 . y1 = F2 . y2 by ZFMISC_1:6;
( y1 in dom F2 & y2 in dom F2 ) by A10, A11, A12, A22, A24, A25, FUNCT_2:def 1;
hence y1 = y2 by A7, A32, FUNCT_1:def 8; :: thesis: verum
end;
set G2 = L (#) F2;
A33: dom (L (#) F2) = Seg (len (L (#) F2)) by FINSEQ_1:def 3;
reconsider f = f as Permutation of (dom F1) by A16, A23, FUNCT_2:83;
( dom F1 = Seg (len F1) & dom (L (#) F1) = Seg (len (L (#) F1)) ) by FINSEQ_1:def 3;
then reconsider f = f as Permutation of (dom (L (#) F1)) by A21;
A34: len (L (#) F2) = len F2 by Def8;
A35: dom (L (#) F1) = Seg (len (L (#) F1)) by FINSEQ_1:def 3;
now
let i be Element of NAT ; :: thesis: ( i in dom (L (#) F2) implies (L (#) F2) . i = (L (#) F1) . (f . i) )
assume A36: i in dom (L (#) F2) ; :: thesis: (L (#) F2) . i = (L (#) F1) . (f . i)
then A37: ( (L (#) F2) . i = (L . (F2 /. i)) * (F2 /. i) & F2 . i = F2 /. i ) by A34, A12, A33, Def8, PARTFUN1:def 8;
i in dom F2 by A34, A36, FINSEQ_3:31;
then reconsider u = F2 . i as Element of V by FINSEQ_2:13;
i in dom f by A10, A21, A34, A35, A33, A36, FUNCT_2:def 1;
then A38: f . i in dom F1 by A16, FUNCT_1:def 5;
then reconsider m = f . i as Element of NAT by A11;
reconsider v = F1 . m as Element of V by A38, FINSEQ_2:13;
{(F1 . (f . i))} = Im (F1,(f . i)) by A38, FUNCT_1:117
.= F1 .: (F1 " {(F2 . i)}) by A10, A34, A11, A33, A15, A36 ;
then A39: u = v by FUNCT_1:145, ZFMISC_1:24;
F1 . m = F1 /. m by A38, PARTFUN1:def 8;
hence (L (#) F2) . i = (L (#) F1) . (f . i) by A21, A11, A35, A38, A39, A37, Def8; :: thesis: verum
end;
hence v1 = v2 by A1, A4, A5, A6, A7, A8, A9, A21, A34, FINSEQ_1:65, RLVECT_2:8; :: thesis: verum