`PhysMeasureBasis.countable_null` {α : Type*} [MeasurableSpace α] [MeasurableSingletonClass α] (μ : Measure α) [NullSingletonClass μ] {s : Set α} (hs : s.Countable) : μ s = 0

Proved

PhysMeasureBasis.countable_null

by leonardopedro · Oct 10, 2026 · Mathlib 0df444a (Lean v4.33.1)

theoremstimepiece

Prove the following Lean 4 theorem from PhysMeasureBasis.

PhysMeasureBasis.countable_null {α : Type*} [MeasurableSpace α] [MeasurableSingletonClass α] (μ : Measure α) [NullSingletonClass μ] {s : Set α} (hs : s.Countable) : μ s = 0

Formalization note: Lean 4 identifier PhysMeasureBasis.countable_null.

Preamble

-- Generated from PhysMeasureBasis.lean — theorem PhysMeasureBasis.countable_null
import Mathlib
import Definitions.Def_PhysMeasureBasis
import Definitions.Def_ChapterA4
open PhysMeasureBasis


open MeasureTheory Set ProbabilityTheory
open scoped ENNReal

noncomputable section

Formal statement

theorem PhysMeasureBasis.countable_null {α : Type*} [MeasurableSpace α]
    [MeasurableSingletonClass α] (μ : Measure α) [NullSingletonClass μ]
    {s : Set α} (hs : s.Countable) : μ s = 0 := by sorry

View graph