for IAlph, OAlph being non empty set
for tfsm1, tfsm2 being non empty finite Mealy-FSM over IAlph,OAlph ex fsm1, fsm2 being non empty finite Mealy-FSM over IAlph,OAlph st
( the carrier of fsm1 misses the carrier of fsm2 & fsm1,tfsm1 -are_isomorphic & fsm2,tfsm2 -are_isomorphic )