reserve k,n,i,j for Nat;

theorem
  for G being Group, f1,f2 being FinSequence of G
    holds (Product (f1^f2))" = (Product f2)" * (Product f1)"
proof
  let G be Group,f1,f2 be FinSequence of G;
  thus (Product (f1^f2))" = ((Product f1) * (Product f2))" by GROUP_4:5
    .= (Product f2)" * (Product f1)" by GROUP_1:17;
end;
