proposition: Lemma umallbF p k f : um_allb p f -> um_allb p (free f k).
proof: Proof. by move/umallbP=>H; apply/umallbP=>kv /InF [_ _ /H]. Qed.
imports: Coq(ssreflect ssrbool ssrfun) mathcomp(ssrnat eqtype seq path bigop) pcm(options prelude finmap seqperm pred seqext) pcm(pcm morphism)