proposition: Lemma ummonoUnL f1 f2 : valid (f1 \+ f2) -> um_mono (f1 \+ f2) -> um_mono f1.
proof: Proof. by move=>W /ummonoP H; apply/ummonoP=>??????; apply: H; apply/InL. Qed.
imports: Coq(ssreflect ssrbool ssrfun) mathcomp(ssrnat eqtype seq path bigop) pcm(options prelude finmap seqperm pred seqext) pcm(pcm morphism)