Documentation

BrownianMotion.StochasticIntegral.OptionalSampling

theorem MeasureTheory.Martingale.condExp_stoppedValue_stopping_time_ae_eq_restrict_le_of_countable_range {ι : Type u_1} {Ω : Type u_2} [LinearOrder ι] [TopologicalSpace ι] [OrderTopology ι] [OrderBot ι] [MeasurableSpace ι] [SecondCountableTopology ι] [BorelSpace ι] [TopologicalSpace.MetrizableSpace ι] { : MeasurableSpace Ω} {𝓕 : Filtration ι } {μ : Measure Ω} [IsFiniteMeasure μ] {X : ιΩ} {τ σ : ΩWithTop ι} (h : Martingale X 𝓕 μ) (hRC : ∀ (ω : Ω), Function.RightContinuous fun (x : ι) => X x ω) {i : ι} (hτ_le : ∀ (x : Ω), τ x i) ( : IsStoppingTime 𝓕 τ) ( : IsStoppingTime 𝓕 σ) (hτ_countable_range : (Set.range τ).Countable) :
theorem MeasureTheory.Martingale.stoppedValue_min_ae_eq_condExp_of_countable_range {ι : Type u_1} {Ω : Type u_2} [LinearOrder ι] [TopologicalSpace ι] [OrderTopology ι] [OrderBot ι] [MeasurableSpace ι] [SecondCountableTopology ι] [BorelSpace ι] [TopologicalSpace.MetrizableSpace ι] { : MeasurableSpace Ω} {𝓕 : Filtration ι } {μ : Measure Ω} [IsFiniteMeasure μ] {X : ιΩ} {τ σ : ΩWithTop ι} (h : Martingale X 𝓕 μ) (hRC : ∀ (ω : Ω), Function.RightContinuous fun (x : ι) => X x ω) ( : IsStoppingTime 𝓕 τ) ( : IsStoppingTime 𝓕 σ) {n : ι} (hτ_le : ∀ (x : Ω), τ x n) (hτ_countable_range : (Set.range τ).Countable) (hσ_countable_range : (Set.range σ).Countable) :
(stoppedValue X fun (x : Ω) => min (σ x) (τ x)) =ᶠ[ae μ] μ[stoppedValue X τ|.measurableSpace]
theorem MeasureTheory.Martingale.stoppedValue_min_ae_eq_condExp_of_discreteApproxSequence {ι : Type u_1} {Ω : Type u_2} [LinearOrder ι] [TopologicalSpace ι] [OrderTopology ι] [OrderBot ι] [MeasurableSpace ι] [SecondCountableTopology ι] [BorelSpace ι] [TopologicalSpace.MetrizableSpace ι] { : MeasurableSpace Ω} {𝓕 : Filtration ι } {μ : Measure Ω} [IsFiniteMeasure μ] {X : ιΩ} {τ σ : ΩWithTop ι} (h : Martingale X 𝓕 μ) (hRC : ∀ (ω : Ω), Function.RightContinuous fun (x : ι) => X x ω) ( : IsStoppingTime 𝓕 τ) ( : IsStoppingTime 𝓕 σ) {n : ι} (hτ_le : ∀ (x : Ω), τ x n) (τn : DiscreteApproxSequence 𝓕 τ μ) (σn : DiscreteApproxSequence 𝓕 σ μ) :
(stoppedValue X fun (x : Ω) => min (τ x) (σ x)) =ᶠ[ae μ] μ[stoppedValue X τ|.measurableSpace]

Optional sampling theorem for general time indices (assuming existence of DiscreteApproxSequence).

theorem MeasureTheory.Martingale.stoppedValue_min_ae_eq_condExp' {ι : Type u_1} {Ω : Type u_2} [LinearOrder ι] [TopologicalSpace ι] [OrderTopology ι] [OrderBot ι] [MeasurableSpace ι] [SecondCountableTopology ι] [BorelSpace ι] [TopologicalSpace.MetrizableSpace ι] { : MeasurableSpace Ω} {𝓕 : Filtration ι } {μ : Measure Ω} [IsFiniteMeasure μ] {X : ιΩ} {τ σ : ΩWithTop ι} [Approximable 𝓕 μ] (h : Martingale X 𝓕 μ) (hRC : ∀ (ω : Ω), Function.RightContinuous fun (x : ι) => X x ω) ( : IsStoppingTime 𝓕 τ) ( : IsStoppingTime 𝓕 σ) {n : ι} (hτ_le : ∀ (x : Ω), τ x n) :
(stoppedValue X fun (x : Ω) => min (τ x) (σ x)) =ᶠ[ae μ] μ[stoppedValue X τ|.measurableSpace]

Optional sampling theorem for approximable time indices.

theorem MeasureTheory.Martingale.stoppedValue_ae_eq_condExp_of_le_const_of_discreteApproxSequence {ι : Type u_1} {Ω : Type u_2} [LinearOrder ι] [TopologicalSpace ι] [OrderTopology ι] [OrderBot ι] [MeasurableSpace ι] [SecondCountableTopology ι] [BorelSpace ι] [TopologicalSpace.MetrizableSpace ι] { : MeasurableSpace Ω} {𝓕 : Filtration ι } {μ : Measure Ω} [IsFiniteMeasure μ] {X : ιΩ} {τ : ΩWithTop ι} {n : ι} [Approximable 𝓕 μ] (h : Martingale X 𝓕 μ) (hRC : ∀ (ω : Ω), Function.RightContinuous fun (x : ι) => X x ω) ( : IsStoppingTime 𝓕 τ) (hτ_le : ∀ (x : Ω), τ x n) :
theorem MeasureTheory.Submartingale.stoppedValue_min_ae_le_condExp_nat {Ω : Type u_1} {E : Type u_2} { : MeasurableSpace Ω} {P : Measure Ω} [NormedAddCommGroup E] [NormedSpace E] [CompleteSpace E] {σ τ : ΩWithTop } {X : ΩE} (𝓕 : Filtration ) [PartialOrder E] [OrderClosedTopology E] [IsOrderedModule E] [IsOrderedAddMonoid E] (hX : Submartingale X 𝓕 P) {k : } (hτk : ∀ᵐ (ω : Ω) P, τ ω k) ( : IsStoppingTime 𝓕 σ) ( : IsStoppingTime 𝓕 τ) :
theorem MeasureTheory.Supermartingale.condExp_ae_le_stoppedValue_min_nat {Ω : Type u_1} {E : Type u_2} { : MeasurableSpace Ω} {P : Measure Ω} [NormedAddCommGroup E] [NormedSpace E] [CompleteSpace E] {σ τ : ΩWithTop } {X : ΩE} (𝓕 : Filtration ) [PartialOrder E] [OrderClosedTopology E] [IsOrderedModule E] [IsOrderedAddMonoid E] (hX : Supermartingale X 𝓕 P) {k : } (hτk : ∀ᵐ (ω : Ω) P, τ ω k) ( : IsStoppingTime 𝓕 σ) ( : IsStoppingTime 𝓕 τ) :
theorem MeasureTheory.Submartingale.stoppedValue_min_ae_le_condExp {Ω : Type u_1} {E : Type u_2} { : MeasurableSpace Ω} {P : Measure Ω} [NormedAddCommGroup E] [NormedSpace E] [CompleteSpace E] {ι : Type u_3} [LinearOrder ι] [TopologicalSpace ι] [OrderTopology ι] [OrderBot ι] [MeasurableSpace ι] [SecondCountableTopology ι] [BorelSpace ι] [TopologicalSpace.MetrizableSpace ι] {σ τ : ΩWithTop ι} {X : ιΩE} (𝓕 : Filtration ι ) [PartialOrder E] [OrderClosedTopology E] [IsOrderedModule E] [IsOrderedAddMonoid E] (hX1 : Submartingale X 𝓕 P) (hX2 : ∀ (ω : Ω), Function.RightContinuous fun (x : ι) => X x ω) {k : ι} (hτk : ∀ᵐ (ω : Ω) P, τ ω k) ( : IsStoppingTime 𝓕 σ) ( : IsStoppingTime 𝓕 τ) :