proposition: Lemma nondecreasing_bounded_variation a b f : {in `[a, b] &, {homo f : x y / x <= y}} -> BV a b f.
proof: Proof. move=> incf; exists (f b - f a) => ? [l pabl <-]; rewrite le_eqVlt. by rewrite nondecreasing_variation// eqxx. Qed.
imports: mathcomp(all_ssreflect ssralg ssrint ssrnum finmap) mathcomp(matrix interval zmodp vector fieldext falgebra) mathcomp(mathcomp_extra boolp classical_sets functions) mathcomp(cardinality) ereal reals signed topology prodnormedzmodule normedtype derive sequences real_interval HB(structures)