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Learning.absolutelyContinuous_uniformAlgorithmπŸ”—

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absolutelyContinuous_uniformAlgorithmπŸ”—

LemmaLearning.absolutelyContinuous_uniformAlgorithm

No docstring.

πŸ”—theorem
Learning.absolutelyContinuous_uniformAlgorithm.{u_1, u_2} {𝓐 : Type u_1} {𝓨 : Type u_2} {m𝓐 : MeasurableSpace 𝓐} {m𝓨 : MeasurableSpace 𝓨} [Finite 𝓐] [Nonempty 𝓐] {alg : Algorithm 𝓐 𝓨} : Algorithm.AbsolutelyContinuous alg uniformAlgorithm
Learning.absolutelyContinuous_uniformAlgorithm.{u_1, u_2} {𝓐 : Type u_1} {𝓨 : Type u_2} {m𝓐 : MeasurableSpace 𝓐} {m𝓨 : MeasurableSpace 𝓨} [Finite 𝓐] [Nonempty 𝓐] {alg : Algorithm 𝓐 𝓨} : Algorithm.AbsolutelyContinuous alg uniformAlgorithm

Code

lemma absolutelyContinuous_uniformAlgorithm [Finite 𝓐] [Nonempty 𝓐] {alg : Algorithm 𝓐 𝓨} :
    alg β‰ͺₐ uniformAlgorithm where
  p0
Type uses (3)
Body uses (3)
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Proof
Measure.absolutelyContinuous_of_measure_singleton_ne_zero
    (by simp [uniformAlgorithm, uniformOn, ← pos_iff_ne_zero, cond_pos_of_inter_ne_zero])
  policy n h := Measure.absolutelyContinuous_of_measure_singleton_ne_zero
    (by simp [uniformAlgorithm, uniformOn, ← pos_iff_ne_zero, cond_pos_of_inter_ne_zero])

Dependency graph

Type dependencies (3)

AlgorithmπŸ”—

StructureLearning.Algorithm

A stochastic, sequential algorithm.

πŸ”—structure
Learning.Algorithm.{u_4, u_5} (𝓐 : Type u_4) (𝓨 : Type u_5) [MeasurableSpace 𝓐] [MeasurableSpace 𝓨] : Type (max u_4 u_5)
Learning.Algorithm.{u_4, u_5} (𝓐 : Type u_4) (𝓨 : Type u_5) [MeasurableSpace 𝓐] [MeasurableSpace 𝓨] : Type (max u_4 u_5)

Code

structure Algorithm (𝓐 𝓨 : Type*) [MeasurableSpace 𝓐] [MeasurableSpace 𝓨] where
  /-- Policy or sampling rule: distribution of the next action. -/
  policy : (n : β„•) β†’ Kernel (Iic n β†’ 𝓐 Γ— 𝓨) 𝓐
  /-- The policy is a Markov kernel. -/
  [h_policy : βˆ€ n, IsMarkovKernel (policy n)]
  /-- Distribution of the first action. -/
  p0 : Measure 𝓐
  /-- The first action distribution is a probability measure. -/
  [hp0 : IsProbabilityMeasure p0]
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AbsolutelyContinuousπŸ”—

StructureLearning.Algorithm.AbsolutelyContinuous

For every time and history, the distribution over actions according to alg is absolutely continuous with respect to the distribution over actions according to algβ‚€.

πŸ”—structure
Learning.Algorithm.AbsolutelyContinuous.{u_1, u_2} {𝓐 : Type u_1} {𝓨 : Type u_2} [MeasurableSpace 𝓐] [MeasurableSpace 𝓨] (alg algβ‚€ : Algorithm 𝓐 𝓨) : Prop
Learning.Algorithm.AbsolutelyContinuous.{u_1, u_2} {𝓐 : Type u_1} {𝓨 : Type u_2} [MeasurableSpace 𝓐] [MeasurableSpace 𝓨] (alg algβ‚€ : Algorithm 𝓐 𝓨) : Prop

Code

structure AbsolutelyContinuous (alg algβ‚€ : Algorithm 𝓐 𝓨) : Prop where
  p0 : alg.p0 β‰ͺ algβ‚€.p0
  policy n h : alg.policy n h β‰ͺ algβ‚€.policy n h
Type uses (1)
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uniformAlgorithmπŸ”—

DefinitionLearning.uniformAlgorithm

The Uniform algorithm: actions are chosen uniformly at random.

πŸ”—def
Learning.uniformAlgorithm.{u_1, u_2} {𝓐 : Type u_1} {𝓨 : Type u_2} {m𝓐 : MeasurableSpace 𝓐} {m𝓨 : MeasurableSpace 𝓨} [Finite 𝓐] [Nonempty 𝓐] : Algorithm 𝓐 𝓨
Learning.uniformAlgorithm.{u_1, u_2} {𝓐 : Type u_1} {𝓨 : Type u_2} {m𝓐 : MeasurableSpace 𝓐} {m𝓨 : MeasurableSpace 𝓨} [Finite 𝓐] [Nonempty 𝓐] : Algorithm 𝓐 𝓨

Code

noncomputable
def uniformAlgorithm [Finite 𝓐] [Nonempty 𝓐] : Algorithm 𝓐 𝓨 := randomSampling (uniformOn Set.univ)
Type uses (1)
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All dependencies, transitively (1)

randomSamplingπŸ”—

DefinitionLearning.randomSampling

The Random Sampling algorithm, which samples from a fixed probability measure at each iteration.

πŸ”—def
Learning.randomSampling.{u_1, u_2} {𝓐 : Type u_1} {𝓨 : Type u_2} {m𝓐 : MeasurableSpace 𝓐} {m𝓨 : MeasurableSpace 𝓨} (ΞΌ : MeasureTheory.Measure 𝓐) [MeasureTheory.IsProbabilityMeasure ΞΌ] : Algorithm 𝓐 𝓨
Learning.randomSampling.{u_1, u_2} {𝓐 : Type u_1} {𝓨 : Type u_2} {m𝓐 : MeasurableSpace 𝓐} {m𝓨 : MeasurableSpace 𝓨} (ΞΌ : MeasureTheory.Measure 𝓐) [MeasureTheory.IsProbabilityMeasure ΞΌ] : Algorithm 𝓐 𝓨

Code

noncomputable def randomSampling (ΞΌ : Measure 𝓐) [IsProbabilityMeasure ΞΌ] : Algorithm 𝓐 𝓨 where
  policy _ := Kernel.const _ ΞΌ
  p0 := ΞΌ
Type uses (1)
Used by (5)

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