proposition: Lemma pexpR_gt1 x : 0 < x -> 1 < expR x.
proof: Proof. by move=> x_gt0; rewrite (lt_le_trans _ (expR_ge1Dx (ltW x_gt0)))// ltrDl. 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