Section SIMU_DETERM_PLUS.
Hypothesis simulation:
forall s1 t s1', Step L1 s1 t s1' ->
forall s2, match_states s1 s2 ->
exists s1'' s2', Star L1 s1' E0 s1'' /\ Plus L2 s2 t s2' /\ match_states s1'' s2'.

Lemma forward_simulation_determ_plus: forward_simulation L1 L2.