for L1, L2 being antisymmetric RelStr
for A1, B1 being Subset of L1 st A1,B1 form_upper_lower_partition_of L1 holds
for A2, B2 being Subset of L2 st A2,B2 form_upper_lower_partition_of L2 holds
for f being Function of (subrelstr A1),(subrelstr A2) st f is isomorphic holds
for g being Function of (subrelstr B1),(subrelstr B2) st g is isomorphic holds
ex h being Function of L1,L2 st
( h = f +* g & h is isomorphic )