proposition: Lemma expRE : expR = fun x => limn (pseries (fun n => (fun n => (n`!%:R)^-1) n) x).
proof: Proof. by apply/funext => x; rewrite /pseries -exp_coeffE. 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