proposition: Lemma dom_difference {A} (m1 m2 : M A) : dom (m1 ∖ m2) ≡ dom m1 ∖ dom m2.
proof: Proof. apply set_equiv. intros i. rewrite elem_of_difference, !elem_of_dom. unfold is_Some. setoid_rewrite lookup_difference_Some. destruct (m2 !! i); naive_solver. Qed.
imports: stdpp(options)