proposition: Lemma updPt k v1 v2 : upd k v1 (pts k v2) = pts k v1 :> U.
proof: Proof. by rewrite !ptsU updU eq_refl. Qed.
imports: Coq(ssreflect ssrbool ssrfun) mathcomp(ssrnat eqtype seq path bigop) pcm(options prelude finmap seqperm pred seqext) pcm(pcm morphism)