reserve S for non void non empty ManySortedSign,
  U1, U2, U3 for non-empty MSAlgebra over S,
  I for set,
  A for ManySortedSet of I,
  B, C for non-empty ManySortedSet of I;

theorem
  for F be ManySortedFunction of U1, U2 st F is_epimorphism U1, U2 for
U3 be non-empty MSAlgebra over S for h1, h2 be ManySortedFunction of U2, U3 st
  h1**F = h2**F holds h1 = h2 by Th12;
