reserve x,O for set,
  o for Element of O,
  G,H,I for GroupWithOperators of O,
  A, B for Subset of G,
  N for normal StableSubgroup of G,
  H1,H2,H3 for StableSubgroup of G,
  g1,g2 for Element of G,
  h1,h2 for Element of H1,
  h for Homomorphism of G,H;

theorem Th35:
  H1 is StableSubgroup of H1 "\/" H2 & H2 is StableSubgroup of H1 "\/" H2
proof
  H1 "\/" H2 = H2 "\/" H1;
  hence thesis by Lm32;
end;
