proposition: Lemma pts_condN k v : ~~ C k -> pts k v = undef :> U.
proof: Proof. by move=>C'; rewrite ptsU upd_condN. Qed.
imports: Coq(ssreflect ssrbool ssrfun) mathcomp(ssrnat eqtype seq path bigop) pcm(options prelude finmap seqperm pred seqext) pcm(pcm morphism)