
theorem Th6:
  for G1, G2, H1, H2 being Group st G1,H1 are_isomorphic & G2,H2
  are_isomorphic holds product <*G1,G2*>, product <*H1,H2*> are_isomorphic
proof
  let G1, G2, H1, H2 be Group;
  given h1 being Homomorphism of G1,H1 such that
A1: h1 is bijective;
  given h2 being Homomorphism of G2,H2 such that
A2: h2 is bijective;
  take Gr2Iso(h1,h2);
  thus thesis by A1,A2,Th5;
end;
