End BACKWARD_SIMU_DIAGRAMS.
(** ** Backward simulation of transition sequences *)
Section BACKWARD_SIMULATION_SEQUENCES.
Context L1 L2 index order match_states (S: bsim_properties L1 L2 index order match_states).

Lemma bsim_safe:
forall i s1 s2,
match_states i s1 s2 -> safe L1 s1 -> safe L2 s2.