proposition: Lemma idL (U : pcm) : @local_fun U (fun x y => Some x).
proof: Proof. by move=>p x y _ V [<-]; rewrite -joinA. Qed.
imports: Coq(ssreflect ssrbool ssrfun) mathcomp(ssrnat eqtype seq bigop fintype finset) pcm(options axioms prelude seqperm pred seqext)