proposition: Lemma ltr_nXz2r n (hn : n < 0) : {in > 0 & , {mono ((@exprz R)^~ n) : x y /~ x < y}}.
proof: Proof. exact: leW_nmono_in (ler_nXz2r _). Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(fintype finfun bigop order ssralg countalg ssrnum) mathcomp(poly)