proposition: Lemma fresh_omfUn h1 h2 : valid (h1 \+ h2) -> fresh (f h1 \+ f h2) <= fresh (h1 \+ h2).
proof: Proof. by move=>W; rewrite -omfUn // fresh_omf. Qed.
imports: Coq(ssreflect ssrbool ssrfun) mathcomp(ssrnat eqtype seq path interval) pcm(options prelude pred finmap rtc seqext useqord uslice uconsec)