theorem :: GROUP_4:17

for G being Group
for F, F1, F2 being FinSequence of the carrier of G st G is commutative Group & len F = len F1 & len F = len F2 & ( for k being Nat st k in dom F holds
F . k = (F1 /. k) * (F2 /. k) ) holds
Product F = (Product F1) * (Product F2)