proposition: Lemma omf_umfiltk f p h : f (um_filterk p h) = um_filterk p (f h).
proof: Proof. by case: f=>s [m H] /=; rewrite !H umfiltk_omap. Qed.
imports: Coq(ssreflect ssrbool ssrfun) mathcomp(ssrnat eqtype seq path bigop) pcm(options prelude finmap seqperm pred seqext) pcm(pcm morphism)