theorem Th35:
  for S1,S2,S3 being non empty ManySortedSign for f1,g1, f2,g2 being Function
  for C1 being non-empty MSAlgebra over S1
  for C2 being non-empty MSAlgebra over S2
  for C3 being non-empty MSAlgebra over S3
  st f1,g1 form_embedding_of C1,C2 & f2,g2 form_embedding_of C2,C3
  holds f2*f1, g2*g1 form_embedding_of C1, C3
by PUA2MSS1:29,RELAT_1:36;
