`BookProof.ChapterG2.not_isProbabilityMeasure_cond_null` (μ : Measure Ω) {C : Set Ω} (hC : μ C = 0) : ¬ IsProbabilityMeasure μ[|C]

Proved

BookProof.ChapterG2.not_isProbabilityMeasure_cond_null

by leonardopedro · Oct 8, 2026 · Mathlib 0df444a (Lean v4.33.1)

theoremstimepiece

Prove the following Lean 4 theorem from ChapterG2.

BookProof.ChapterG2.not_isProbabilityMeasure_cond_null (μ : Measure Ω) {C : Set Ω} (hC : μ C = 0) : ¬ IsProbabilityMeasure μ[|C]

Formalization note: Lean 4 identifier BookProof.ChapterG2.not_isProbabilityMeasure_cond_null.

Preamble

-- Generated from ChapterG2.lean — theorem BookProof.ChapterG2.not_isProbabilityMeasure_cond_null
import Mathlib
import Definitions.Def_ChapterG2
open BookProof.ChapterG2


open MeasureTheory ProbabilityTheory
open scoped ProbabilityTheory

variable {Ω : Type*} [MeasurableSpace Ω]

Formal statement

theorem BookProof.ChapterG2.not_isProbabilityMeasure_cond_null (μ : Measure Ω) {C : Set Ω}
    (hC : μ C = 0) : ¬ IsProbabilityMeasure μ[|C] := by sorry

View graph