proposition: Theorem fmap_lookup : forall a b m, mapsto a b m -> mapsto a (f b) (fmap_pmap m).
proof: Proof. induction a; destruct m; simpl; intros; try congruence. { eapply IHa. eapply H. } { eapply IHa; eapply H. } { subst. auto. } Qed.
imports: ExtLib.Structures.Maps ExtLib.Structures.Functor ExtLib.Data.Option ExtLib.Data.Positive ExtLib.Tactics.Cases