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 Th17:
  U1,U2 are_similar implies MSAlg h is ManySortedSet of {0}
proof
  assume U1,U2 are_similar;
  then MSAlg h = 0 .--> h by Def3,Th10;
  hence thesis;
end;
