proposition: Lemma override_neq: forall {V} n1 n2 s (v1 v2: V), n1 <> n2 -> SysPredefs.override (SysPredefs.override s n1 v1) n2 v2 = SysPredefs.override (SysPredefs.override s n2 v2) n1 v1.
proof: Proof. unfold SysPredefs.override; intros. apply functional_extensionality; intros. case_eq (x =_? n2); intros; subst; auto. case_eq (n2 =_? n1); intros; subst; auto. congruence. Qed.
imports: Coq(FunctionalExtensionality List Arith Lia) Chapar(Predefs KVStore)