let L be non empty multMagma ; :: thesis: for p, q, r being sequence of L
for t being FinSequence of 3 -tuples_on NAT
for P being Permutation of (dom t)
for t1 being FinSequence of 3 -tuples_on NAT st t1 = t * P holds
prodTuples p,q,r,t1 = (prodTuples p,q,r,t) * P

let p, q, r be sequence of L; :: thesis: for t being FinSequence of 3 -tuples_on NAT
for P being Permutation of (dom t)
for t1 being FinSequence of 3 -tuples_on NAT st t1 = t * P holds
prodTuples p,q,r,t1 = (prodTuples p,q,r,t) * P

let t be FinSequence of 3 -tuples_on NAT ; :: thesis: for P being Permutation of (dom t)
for t1 being FinSequence of 3 -tuples_on NAT st t1 = t * P holds
prodTuples p,q,r,t1 = (prodTuples p,q,r,t) * P

let P be Permutation of (dom t); :: thesis: for t1 being FinSequence of 3 -tuples_on NAT st t1 = t * P holds
prodTuples p,q,r,t1 = (prodTuples p,q,r,t) * P

let t1 be FinSequence of 3 -tuples_on NAT ; :: thesis: ( t1 = t * P implies prodTuples p,q,r,t1 = (prodTuples p,q,r,t) * P )
assume A1: t1 = t * P ; :: thesis: prodTuples p,q,r,t1 = (prodTuples p,q,r,t) * P
len (prodTuples p,q,r,t1) = len t1 by Def5;
then A2: dom (prodTuples p,q,r,t1) = Seg (len t1) by FINSEQ_1:def 3;
A3: rng P = dom t by FUNCT_2:def 3;
len (prodTuples p,q,r,t) = len t by Def5;
then A4: rng P = dom (prodTuples p,q,r,t) by A3, FINSEQ_3:31;
A5: dom P = dom t1 by A1, A3, RELAT_1:46;
then A6: dom ((prodTuples p,q,r,t) * P) = dom t1 by A4, RELAT_1:46;
A7: dom t1 = Seg (len t1) by FINSEQ_1:def 3;
now
let x be set ; :: thesis: ( x in dom t1 implies (prodTuples p,q,r,t1) . x = ((prodTuples p,q,r,t) * P) . x )
assume A8: x in dom t1 ; :: thesis: (prodTuples p,q,r,t1) . x = ((prodTuples p,q,r,t) * P) . x
then reconsider i = x as Element of NAT ;
A9: P . i in rng P by A5, A8, FUNCT_1:def 5;
reconsider j = P . i as Element of NAT ;
A10: (prodTuples p,q,r,t1) . i = ((p . ((t1 /. i) /. 1)) * (q . ((t1 /. i) /. 2))) * (r . ((t1 /. i) /. 3)) by A8, Def5;
A11: ((prodTuples p,q,r,t) * P) . x = (prodTuples p,q,r,t) . (P . x) by A5, A8, FUNCT_1:23;
t1 /. i = t1 . i by A8, PARTFUN1:def 8
.= t . (P . i) by A1, A8, FUNCT_1:22
.= t /. j by A3, A9, PARTFUN1:def 8 ;
hence (prodTuples p,q,r,t1) . x = ((prodTuples p,q,r,t) * P) . x by A3, A9, A10, A11, Def5; :: thesis: verum
end;
hence prodTuples p,q,r,t1 = (prodTuples p,q,r,t) * P by A2, A6, A7, FUNCT_1:9; :: thesis: verum