reserve U1,U2,U3 for Universal_Algebra,
  m,n for Nat,
  a for set,
  A for non empty set,
  h for Function of U1,U2;

theorem
  for U1, U2, h st U1, U2 are_similar holds MSAlg h is_isomorphism MSAlg
  U1, (MSAlg U2 Over MSSign U1) implies h is_isomorphism
by Th23,Th22;
