proposition: Lemma R_concave_function_atN f a b t : convex_function_at f a b t -> concave_function_at (fun x => - f x)%coqR a b t.
proof: Proof. rewrite /concave_function_at /convex_function_at. by rewrite /leconv/= /leopp/= avgR_oppD /leconv/= leR_oppl oppRK. Qed.
imports: HB(structures) mathcomp(all_ssreflect ssralg fingroup perm matrix) mathcomp(mathcomp_extra boolp classical_sets Rstruct) mathcomp(ssrnum ereal) mathcomp(lra Rstruct reals) Reals ssrR Reals_ext Ranalysis_ext ssr_ext ssralg_ext logb realType_ext fdist