reserve X for non empty BCIStr_1;
reserve d for Element of X;
reserve n,m,k for Nat;
reserve f for sequence of  the carrier of X;

theorem
  for X being BCI-Algebra_with_Condition(S), F1,F2 being FinSequence of
  the carrier of X holds Product_S(F1 ^ F2) = Product_S(F1) * Product_S(F2) by
