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teorth/PFR
Source indexedlemma · leanprover/lean4:v4.33.0-rc1

ProbabilityTheory.measureMutualInfo_of_not_isFiniteMeasure

PFR.ForMathlib.Entropy.Measure · PFR/ForMathlib/Entropy/Measure.lean:523 to 536

Mathematical statement

Exact Lean statement

lemma measureMutualInfo_of_not_isFiniteMeasure {μ : Measure (S × U)} (h : ¬ IsFiniteMeasure μ) :
    Im[μ] = 0

Complete declaration

Lean source

Canonical source
Full Lean sourceLean 4
lemma measureMutualInfo_of_not_isFiniteMeasure {μ : Measure (S × U)} (h : ¬ IsFiniteMeasure μ) :    Im[μ] = 0 := by  rw [measureMutualInfo_def]  have h1 : ¬ IsFiniteMeasure (μ.map Prod.fst) := by    rw [not_isFiniteMeasure_iff] at h     rw [ h]    exact Measure.map_apply measurable_fst MeasurableSet.univ  have h2 : ¬ IsFiniteMeasure (μ.map Prod.snd) := by    rw [not_isFiniteMeasure_iff] at h     rw [ h]    exact Measure.map_apply measurable_snd MeasurableSet.univ  rw [measureEntropy_of_not_isFiniteMeasure h, measureEntropy_of_not_isFiniteMeasure h1,    measureEntropy_of_not_isFiniteMeasure h2]  simp