proposition: Lemma lastatval0 v : last_atval v Unit = v.
proof: Proof. by rewrite /last_atval /atval lastkey0 find0E. Qed.
imports: Coq(ssreflect ssrbool ssrfun) mathcomp(ssrnat eqtype seq path interval) pcm(options prelude pred finmap rtc seqext useqord uslice uconsec)