proposition: Lemma range_oppe : range -%E = [set: \bar R]%classic.
proof: Proof. by apply/seteqP; split => [//|x] _; exists (- x); rewrite ?oppeK. Qed.
imports: HB(structures) mathcomp(all_ssreflect all_algebra finmap) mathcomp(mathcomp_extra boolp classical_sets functions) mathcomp(fsbigop cardinality set_interval) reals signed topology constructive_ereal