proposition: Lemma updUnPt k v1 v2 f : upd k v1 (f \+ pts k v2) = f \+ pts k v1.
proof: Proof. by rewrite !(joinC f); apply: updPtUn. Qed.
imports: Coq(ssreflect ssrbool ssrfun) mathcomp(ssrnat eqtype seq path bigop) pcm(options prelude finmap seqperm pred seqext) pcm(pcm morphism)