proposition: Lemma lastval_mem_none kv h : last_val h = None -> kv \Notin h.
proof: Proof. by case: lastvalP. Qed.
imports: Coq(ssreflect ssrbool ssrfun) mathcomp(ssrnat eqtype seq path interval) pcm(options prelude pred finmap rtc seqext useqord uslice uconsec)