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Bandits.StreamMeasure.prob_sum_range_sub_ge_le_of_HasSubgaussianMGF๐Ÿ”—

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prob_sum_range_sub_ge_le_of_HasSubgaussianMGF๐Ÿ”—

LemmaBandits.StreamMeasure.prob_sum_range_sub_ge_le_of_HasSubgaussianMGF

No docstring.

๐Ÿ”—theorem
Bandits.StreamMeasure.prob_sum_range_sub_ge_le_of_HasSubgaussianMGF.{u_1} {๐“ : Type u_1} {m๐“ : MeasurableSpace ๐“} {ฮฝ : ProbabilityTheory.Kernel ๐“ โ„} [ProbabilityTheory.IsMarkovKernel ฮฝ] {a : ๐“} {ฯƒ2 : NNReal} (h : ProbabilityTheory.HasSubgaussianMGF (fun x => x - โˆซ (x : โ„), id x โˆ‚ฮฝ a) ฯƒ2 (ฮฝ a)) {ฮต : โ„} (hฮต : 0 โ‰ค ฮต) (n : โ„•) : (streamMeasure ฮฝ) {ฯ‰ | ฮต โ‰ค โˆ‘ k โˆˆ Finset.range n, (ฯ‰ k a - โˆซ (x : โ„), id x โˆ‚ฮฝ a)} โ‰ค ENNReal.ofReal (Real.exp (-ฮต ^ 2 / (2 * โ†‘n * โ†‘ฯƒ2)))
Bandits.StreamMeasure.prob_sum_range_sub_ge_le_of_HasSubgaussianMGF.{u_1} {๐“ : Type u_1} {m๐“ : MeasurableSpace ๐“} {ฮฝ : ProbabilityTheory.Kernel ๐“ โ„} [ProbabilityTheory.IsMarkovKernel ฮฝ] {a : ๐“} {ฯƒ2 : NNReal} (h : ProbabilityTheory.HasSubgaussianMGF (fun x => x - โˆซ (x : โ„), id x โˆ‚ฮฝ a) ฯƒ2 (ฮฝ a)) {ฮต : โ„} (hฮต : 0 โ‰ค ฮต) (n : โ„•) : (streamMeasure ฮฝ) {ฯ‰ | ฮต โ‰ค โˆ‘ k โˆˆ Finset.range n, (ฯ‰ k a - โˆซ (x : โ„), id x โˆ‚ฮฝ a)} โ‰ค ENNReal.ofReal (Real.exp (-ฮต ^ 2 / (2 * โ†‘n * โ†‘ฯƒ2)))

Code

lemma prob_sum_range_sub_ge_le_of_HasSubgaussianMGF {ฯƒ2 : โ„โ‰ฅ0}
    (h : HasSubgaussianMGF (fun x โ†ฆ x - (ฮฝ a)[id]) ฯƒ2 (ฮฝ a)) {ฮต : โ„} (hฮต : 0 โ‰ค ฮต) (n : โ„•) :
    streamMeasure ฮฝ {ฯ‰ | ฮต โ‰ค โˆ‘ k โˆˆ range n, (ฯ‰ k a - (ฮฝ a)[id])} โ‰ค
      ENNReal.ofReal (Real.exp (-ฮต ^ 2 / (2 * n * ฯƒ2)))
Type uses (1)
Body uses (3)
Used by (1)

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Proof
by
  rw [โ† ofReal_measureReal]
  gcongr
  apply HasSubgaussianMGF.measure_sum_range_ge_le_of_iIndepFun _ _ hฮต
  ยท exact (iIndepFun_eval_streamMeasure'' ฮฝ a).comp (fun _ x โ†ฆ x - (ฮฝ a)[id]) (by fun_prop)
  ยท intro _ _
    exact h.congr_identDistrib ((identDistrib_eval_eval_id_streamMeasure _ _ _).symm.sub_const _)

Dependency graph

Type dependencies (1)

streamMeasure๐Ÿ”—

DefinitionBandits.streamMeasure

Measure of an infinite stream of rewards from each action.

๐Ÿ”—def
Bandits.streamMeasure.{u_1, u_2} {๐“ : Type u_1} {R : Type u_2} {m๐“ : MeasurableSpace ๐“} {mR : MeasurableSpace R} (ฮฝ : ProbabilityTheory.Kernel ๐“ R) : MeasureTheory.Measure (โ„• โ†’ ๐“ โ†’ R)
Bandits.streamMeasure.{u_1, u_2} {๐“ : Type u_1} {R : Type u_2} {m๐“ : MeasurableSpace ๐“} {mR : MeasurableSpace R} (ฮฝ : ProbabilityTheory.Kernel ๐“ R) : MeasureTheory.Measure (โ„• โ†’ ๐“ โ†’ R)

Code

noncomputable
def streamMeasure (ฮฝ : Kernel ๐“ R) : Measure (โ„• โ†’ ๐“ โ†’ R) :=
  Measure.infinitePi fun _ โ†ฆ Measure.infinitePi ฮฝ
Used by (56)

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