proposition: Lemma measurable_set1Ny : G.-sigma.-measurable [set -oo].
proof: Proof. rewrite eset1Ny; apply: bigcap_measurable => i _. rewrite -setCitvr; apply: measurableC; rewrite (eitv_bnd_infty false). apply: bigcap_measurable => j _; apply: sub_sigma_algebra. by exists (- (i%:R + j.+1%:R^-1))%R; rewrite opprD. Qed.
imports: mathcomp(all_ssreflect ssralg ssrnum ssrint interval) mathcomp(finmap fingroup perm rat) mathcomp(mathcomp_extra boolp classical_sets functions) mathcomp(cardinality fsbigop) reals ereal signed topology numfun normedtype HB(structures) sequences esum measure real_interval realfun exp lebesgue_stieltjes_measure