proposition: Lemma umcntUnPt p k v f : valid (f \+ pts k v) -> um_count p (f \+ pts k v) = um_count p f + if p (k, v) then 1 else 0.
proof: Proof. by rewrite joinC=>W; rewrite umcntPtUn // addnC. Qed.
imports: Coq(ssreflect ssrbool ssrfun) mathcomp(ssrnat eqtype seq path bigop) pcm(options prelude finmap seqperm pred seqext) pcm(pcm morphism)