proposition: Lemma eqopp_le x y : x = y <-> leopp x y /\ leopp y x.
proof: Proof. by split; [move ->; move: leoppR |move: x y => [x'] [y'] => /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