proposition: Lemma ae_eq_sym f g : ae_eq f g -> ae_eq g f.
proof: Proof. by apply: filterS => x + Dx => /(_ Dx). Qed.
imports: mathcomp(all_ssreflect all_algebra finmap) mathcomp(mathcomp_extra boolp classical_sets functions) mathcomp(cardinality fsbigop ) reals ereal signed topology normedtype sequences esum numfun HB(structures)