`BookProof.ChapterMAPNull.countable_map_set_measure_zero` (μ : Measure α) [NullSingletonClass μ] (maximizers : Set α) (hcountable : maximizers.Countable) : μ maximizers = 0

Proved

BookProof.ChapterMAPNull.countable_map_set_measure_zero

by leonardopedro · Oct 9, 2026 · Mathlib 0df444a (Lean v4.33.1)

theoremstimepiece

Prove the following Lean 4 theorem from ChapterMAPNull.

BookProof.ChapterMAPNull.countable_map_set_measure_zero (μ : Measure α) [NullSingletonClass μ] (maximizers : Set α) (hcountable : maximizers.Countable) : μ maximizers = 0

Formalization note: Lean 4 identifier BookProof.ChapterMAPNull.countable_map_set_measure_zero.

Preamble

-- Generated from ChapterMAPNull.lean — theorem BookProof.ChapterMAPNull.countable_map_set_measure_zero
import Mathlib
import Definitions.Def_ChapterMAPNull
open BookProof.ChapterMAPNull


open MeasureTheory


variable {α : Type*} [MeasurableSpace α]

Formal statement

theorem BookProof.ChapterMAPNull.countable_map_set_measure_zero (μ : Measure α) [NullSingletonClass μ]
    (maximizers : Set α) (hcountable : maximizers.Countable) :
    μ maximizers = 0 := by sorry

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