let n be Nat; for ITP being Element of Permutations n
for ITG being Element of (Group_of_Perm n) st ITG = ITP & n >= 1 holds
ITP " = ITG "
let ITP be Element of Permutations n; for ITG being Element of (Group_of_Perm n) st ITG = ITP & n >= 1 holds
ITP " = ITG "
let ITG be Element of (Group_of_Perm n); ( ITG = ITP & n >= 1 implies ITP " = ITG " )
assume that
A1:
ITG = ITP
and
A2:
n >= 1
; ITP " = ITG "
reconsider qf = ITP as Function of (Seg n),(Seg n) by MATRIX_2:def 9;
dom qf = Seg n
by A2, FUNCT_2:def 1;
then A3:
(ITP ") * ITP = id (Seg n)
by FUNCT_1:39;
ITP is Permutation of (Seg n)
by MATRIX_2:def 9;
then
rng qf = Seg n
by FUNCT_2:def 3;
then A4:
ITP * (ITP ") = id (Seg n)
by FUNCT_1:39;
reconsider pf = ITP " as Element of (Group_of_Perm n) by MATRIX_2:def 10;
A5:
( idseq n = 1_ (Group_of_Perm n) & ITG * pf = the multF of (Group_of_Perm n) . (ITG,pf) )
by MATRIX_2:24;
A6:
pf * ITG = the multF of (Group_of_Perm n) . (pf,ITG)
;
( the multF of (Group_of_Perm n) . (ITG,pf) = (ITP ") * ITP & the multF of (Group_of_Perm n) . (pf,ITG) = ITP * (ITP ") )
by A1, MATRIX_2:def 10;
hence
ITP " = ITG "
by A3, A4, A5, A6, GROUP_1:def 5; verum