proposition: Lemma rangeUnPtK k v f : valid (f \+ pts k v) -> all (ord^~ k) (dom f) -> range (f \+ pts k v) = rcons (range f) v.
proof: Proof. by move=>W H; rewrite /range assocsUnPt // map_rcons. Qed.
imports: Coq(ssreflect ssrbool ssrfun) mathcomp(ssrnat eqtype seq path bigop) pcm(options prelude finmap seqperm pred seqext) pcm(pcm morphism)