proposition: Lemma expRD x y : expR (x + y) = expR x * expR y.
proof: Proof. apply: (mulIf (lt0r_neq0 (expR_gt0 (- x)))). rewrite expRxDyMexpx expRN [_ * expR y]mulrC mulfK //. by case: ltrgt0P (expR_gt0 x). 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