proposition: Lemma sub_limX (u : chain tp) : lim [sval ^^ u by sval_mono] \In s.
proof: Proof. by case: C u=>P H u; apply: (H)=>t [[y]] H1 [->]. Qed.
imports: mathcomp(ssreflect ssrbool ssrfun ssrnat eqtype seq) pcm(options axioms pred prelude)