proposition: Lemma preimage_abse_ninfty : (@abse R @^-1` [set -oo])%classic = set0.
proof: Proof. rewrite predeqE => t; split => //=; apply/eqP. by rewrite gt_eqF// (lt_le_trans _ (abse_ge0 t)). 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