proposition: Lemma eqfun_le f g : f = g <-> lefun f g /\ lefun g f.
proof: Proof. split; [move ->; by move: lefunR |]. case=> Hfg Hgh; rewrite funeqE => a. move : (Hfg a) (Hgh a) => Hfg' Hgh'; exact/eqconv_le. 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