proposition: Lemma pseries_diffs_inv_fact : pseries_diffs (fun n => (n`!%:R)^-1) = (fun n => (n`!%:R)^-1 : R).
proof: Proof. apply/funext => i. by rewrite /pseries_diffs factS natrM invfM mulrA mulfV ?mul1r. Qed.
imports: mathcomp(all_ssreflect ssralg ssrint ssrnum matrix) mathcomp(interval rat) mathcomp(boolp classical_sets functions) mathcomp(mathcomp_extra) reals ereal signed topology normedtype landau sequences derive realfun itv convex