intros ? ? ? ? mu mu' ge1 ge2 gsep geq b1 b2 d map1 map2.
rewrite <- (genvs_domain_eq_isGlobal _ _ geq).
eapply gsep; eauto.
Qed.

Lemma gsep_trans:
forall {F V} (ge:  Genv.t F V) mu mu' mu'',
Values.inject_incr (as_inj mu') (as_inj mu'') ->
globals_separate ge mu mu' ->
globals_separate ge mu' mu'' ->
globals_separate ge mu mu''.