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HasLaw.variance_eq {μ : Measure ℝ} {X : Ω → ℝ} (hX : HasLaw X μ P) : Var[X; P] = Var[id; μ] := by rw [← hX.map_eq, variance_map aemeasurable_id hX.aemeasurable, Function.id_comp]
lemma
Probability
[ "Mathlib.Probability.Density", "Mathlib.Probability.Moments.Variance" ]
Mathlib/Probability/HasLaw.lean
HasLaw.variance_eq
null
HasPDF.hasLaw [h : HasPDF X P μ] : HasLaw X (μ.withDensity (pdf X P μ)) P where aemeasurable := h.aemeasurable map_eq := map_eq_withDensity_pdf X P μ
lemma
Probability
[ "Mathlib.Probability.Density", "Mathlib.Probability.Moments.Variance" ]
Mathlib/Probability/HasLaw.lean
HasPDF.hasLaw
null
IdentDistrib (f : α → γ) (g : β → γ) (μ : Measure α := by volume_tac) (ν : Measure β := by volume_tac) : Prop where aemeasurable_fst : AEMeasurable f μ aemeasurable_snd : AEMeasurable g ν map_eq : Measure.map f μ = Measure.map g ν
structure
Probability
[ "Mathlib.Probability.Moments.Variance", "Mathlib.MeasureTheory.Function.UniformIntegrable" ]
Mathlib/Probability/IdentDistrib.lean
IdentDistrib
Two functions defined on two (possibly different) measure spaces are identically distributed if their image measures coincide. This only makes sense when the functions are ae measurable (as otherwise the image measures are not defined), so we require this as well in the definition.
protected refl (hf : AEMeasurable f μ) : IdentDistrib f f μ μ := { aemeasurable_fst := hf aemeasurable_snd := hf map_eq := rfl }
theorem
Probability
[ "Mathlib.Probability.Moments.Variance", "Mathlib.MeasureTheory.Function.UniformIntegrable" ]
Mathlib/Probability/IdentDistrib.lean
refl
null
protected symm (h : IdentDistrib f g μ ν) : IdentDistrib g f ν μ := { aemeasurable_fst := h.aemeasurable_snd aemeasurable_snd := h.aemeasurable_fst map_eq := h.map_eq.symm }
theorem
Probability
[ "Mathlib.Probability.Moments.Variance", "Mathlib.MeasureTheory.Function.UniformIntegrable" ]
Mathlib/Probability/IdentDistrib.lean
symm
null
protected trans {ρ : Measure δ} {h : δ → γ} (h₁ : IdentDistrib f g μ ν) (h₂ : IdentDistrib g h ν ρ) : IdentDistrib f h μ ρ := { aemeasurable_fst := h₁.aemeasurable_fst aemeasurable_snd := h₂.aemeasurable_snd map_eq := h₁.map_eq.trans h₂.map_eq }
theorem
Probability
[ "Mathlib.Probability.Moments.Variance", "Mathlib.MeasureTheory.Function.UniformIntegrable" ]
Mathlib/Probability/IdentDistrib.lean
trans
null
protected comp_of_aemeasurable {u : γ → δ} (h : IdentDistrib f g μ ν) (hu : AEMeasurable u (Measure.map f μ)) : IdentDistrib (u ∘ f) (u ∘ g) μ ν := { aemeasurable_fst := hu.comp_aemeasurable h.aemeasurable_fst aemeasurable_snd := by rw [h.map_eq] at hu; exact hu.comp_aemeasurable h.aemeasurable_snd map_eq...
theorem
Probability
[ "Mathlib.Probability.Moments.Variance", "Mathlib.MeasureTheory.Function.UniformIntegrable" ]
Mathlib/Probability/IdentDistrib.lean
comp_of_aemeasurable
null
protected comp {u : γ → δ} (h : IdentDistrib f g μ ν) (hu : Measurable u) : IdentDistrib (u ∘ f) (u ∘ g) μ ν := h.comp_of_aemeasurable hu.aemeasurable
theorem
Probability
[ "Mathlib.Probability.Moments.Variance", "Mathlib.MeasureTheory.Function.UniformIntegrable" ]
Mathlib/Probability/IdentDistrib.lean
comp
null
protected of_ae_eq {g : α → γ} (hf : AEMeasurable f μ) (heq : f =ᵐ[μ] g) : IdentDistrib f g μ μ := { aemeasurable_fst := hf aemeasurable_snd := hf.congr heq map_eq := Measure.map_congr heq }
theorem
Probability
[ "Mathlib.Probability.Moments.Variance", "Mathlib.MeasureTheory.Function.UniformIntegrable" ]
Mathlib/Probability/IdentDistrib.lean
of_ae_eq
null
_root_.MeasureTheory.AEMeasurable.identDistrib_mk (hf : AEMeasurable f μ) : IdentDistrib f (hf.mk f) μ μ := IdentDistrib.of_ae_eq hf hf.ae_eq_mk
lemma
Probability
[ "Mathlib.Probability.Moments.Variance", "Mathlib.MeasureTheory.Function.UniformIntegrable" ]
Mathlib/Probability/IdentDistrib.lean
_root_.MeasureTheory.AEMeasurable.identDistrib_mk
null
_root_.MeasureTheory.AEStronglyMeasurable.identDistrib_mk [TopologicalSpace γ] [PseudoMetrizableSpace γ] [BorelSpace γ] (hf : AEStronglyMeasurable f μ) : IdentDistrib f (hf.mk f) μ μ := IdentDistrib.of_ae_eq hf.aemeasurable hf.ae_eq_mk
lemma
Probability
[ "Mathlib.Probability.Moments.Variance", "Mathlib.MeasureTheory.Function.UniformIntegrable" ]
Mathlib/Probability/IdentDistrib.lean
_root_.MeasureTheory.AEStronglyMeasurable.identDistrib_mk
null
measure_mem_eq (h : IdentDistrib f g μ ν) {s : Set γ} (hs : MeasurableSet s) : μ (f ⁻¹' s) = ν (g ⁻¹' s) := by rw [← Measure.map_apply_of_aemeasurable h.aemeasurable_fst hs, ← Measure.map_apply_of_aemeasurable h.aemeasurable_snd hs, h.map_eq] alias measure_preimage_eq := measure_mem_eq
theorem
Probability
[ "Mathlib.Probability.Moments.Variance", "Mathlib.MeasureTheory.Function.UniformIntegrable" ]
Mathlib/Probability/IdentDistrib.lean
measure_mem_eq
null
ae_snd (h : IdentDistrib f g μ ν) {p : γ → Prop} (pmeas : MeasurableSet {x | p x}) (hp : ∀ᵐ x ∂μ, p (f x)) : ∀ᵐ x ∂ν, p (g x) := by apply (ae_map_iff h.aemeasurable_snd pmeas).1 rw [← h.map_eq] exact (ae_map_iff h.aemeasurable_fst pmeas).2 hp
theorem
Probability
[ "Mathlib.Probability.Moments.Variance", "Mathlib.MeasureTheory.Function.UniformIntegrable" ]
Mathlib/Probability/IdentDistrib.lean
ae_snd
null
ae_mem_snd (h : IdentDistrib f g μ ν) {t : Set γ} (tmeas : MeasurableSet t) (ht : ∀ᵐ x ∂μ, f x ∈ t) : ∀ᵐ x ∂ν, g x ∈ t := h.ae_snd tmeas ht
theorem
Probability
[ "Mathlib.Probability.Moments.Variance", "Mathlib.MeasureTheory.Function.UniformIntegrable" ]
Mathlib/Probability/IdentDistrib.lean
ae_mem_snd
null
aestronglyMeasurable_fst [TopologicalSpace γ] [PseudoMetrizableSpace γ] [OpensMeasurableSpace γ] [SecondCountableTopology γ] (h : IdentDistrib f g μ ν) : AEStronglyMeasurable f μ := h.aemeasurable_fst.aestronglyMeasurable
theorem
Probability
[ "Mathlib.Probability.Moments.Variance", "Mathlib.MeasureTheory.Function.UniformIntegrable" ]
Mathlib/Probability/IdentDistrib.lean
aestronglyMeasurable_fst
In a second countable topology, the first function in an identically distributed pair is a.e. strongly measurable. So is the second function, but use `h.symm.aestronglyMeasurable_fst` as `h.aestronglyMeasurable_snd` has a different meaning.
aestronglyMeasurable_snd [TopologicalSpace γ] [PseudoMetrizableSpace γ] [BorelSpace γ] (h : IdentDistrib f g μ ν) (hf : AEStronglyMeasurable f μ) : AEStronglyMeasurable g ν := by refine aestronglyMeasurable_iff_aemeasurable_separable.2 ⟨h.aemeasurable_snd, ?_⟩ rcases (aestronglyMeasurable_iff_aemeasurable_separ...
theorem
Probability
[ "Mathlib.Probability.Moments.Variance", "Mathlib.MeasureTheory.Function.UniformIntegrable" ]
Mathlib/Probability/IdentDistrib.lean
aestronglyMeasurable_snd
If `f` and `g` are identically distributed and `f` is a.e. strongly measurable, so is `g`.
aestronglyMeasurable_iff [TopologicalSpace γ] [PseudoMetrizableSpace γ] [BorelSpace γ] (h : IdentDistrib f g μ ν) : AEStronglyMeasurable f μ ↔ AEStronglyMeasurable g ν := ⟨fun hf => h.aestronglyMeasurable_snd hf, fun hg => h.symm.aestronglyMeasurable_snd hg⟩
theorem
Probability
[ "Mathlib.Probability.Moments.Variance", "Mathlib.MeasureTheory.Function.UniformIntegrable" ]
Mathlib/Probability/IdentDistrib.lean
aestronglyMeasurable_iff
null
essSup_eq [ConditionallyCompleteLinearOrder γ] [TopologicalSpace γ] [OpensMeasurableSpace γ] [OrderClosedTopology γ] (h : IdentDistrib f g μ ν) : essSup f μ = essSup g ν := by have I : ∀ a, μ {x : α | a < f x} = ν {x : β | a < g x} := fun a => h.measure_mem_eq measurableSet_Ioi simp_rw [essSup_eq_sInf, I]
theorem
Probability
[ "Mathlib.Probability.Moments.Variance", "Mathlib.MeasureTheory.Function.UniformIntegrable" ]
Mathlib/Probability/IdentDistrib.lean
essSup_eq
null
lintegral_eq {f : α → ℝ≥0∞} {g : β → ℝ≥0∞} (h : IdentDistrib f g μ ν) : ∫⁻ x, f x ∂μ = ∫⁻ x, g x ∂ν := by change ∫⁻ x, id (f x) ∂μ = ∫⁻ x, id (g x) ∂ν rw [← lintegral_map' aemeasurable_id h.aemeasurable_fst, ← lintegral_map' aemeasurable_id h.aemeasurable_snd, h.map_eq]
theorem
Probability
[ "Mathlib.Probability.Moments.Variance", "Mathlib.MeasureTheory.Function.UniformIntegrable" ]
Mathlib/Probability/IdentDistrib.lean
lintegral_eq
null
integral_eq [NormedAddCommGroup γ] [NormedSpace ℝ γ] [BorelSpace γ] (h : IdentDistrib f g μ ν) : ∫ x, f x ∂μ = ∫ x, g x ∂ν := by by_cases hf : AEStronglyMeasurable f μ · have A : AEStronglyMeasurable id (Measure.map f μ) := by rw [aestronglyMeasurable_iff_aemeasurable_separable] rcases (aestronglyMe...
theorem
Probability
[ "Mathlib.Probability.Moments.Variance", "Mathlib.MeasureTheory.Function.UniformIntegrable" ]
Mathlib/Probability/IdentDistrib.lean
integral_eq
null
eLpNorm_eq [NormedAddCommGroup γ] [OpensMeasurableSpace γ] (h : IdentDistrib f g μ ν) (p : ℝ≥0∞) : eLpNorm f p μ = eLpNorm g p ν := by by_cases h0 : p = 0 · simp [h0] by_cases h_top : p = ∞ · simp only [h_top, eLpNorm, eLpNormEssSup, ENNReal.top_ne_zero, if_true, if_false] apply essSup_eq exac...
theorem
Probability
[ "Mathlib.Probability.Moments.Variance", "Mathlib.MeasureTheory.Function.UniformIntegrable" ]
Mathlib/Probability/IdentDistrib.lean
eLpNorm_eq
null
memLp_snd [NormedAddCommGroup γ] [BorelSpace γ] {p : ℝ≥0∞} (h : IdentDistrib f g μ ν) (hf : MemLp f p μ) : MemLp g p ν := by refine ⟨h.aestronglyMeasurable_snd hf.aestronglyMeasurable, ?_⟩ rw [← h.eLpNorm_eq] exact hf.2
theorem
Probability
[ "Mathlib.Probability.Moments.Variance", "Mathlib.MeasureTheory.Function.UniformIntegrable" ]
Mathlib/Probability/IdentDistrib.lean
memLp_snd
null
memLp_iff [NormedAddCommGroup γ] [BorelSpace γ] {p : ℝ≥0∞} (h : IdentDistrib f g μ ν) : MemLp f p μ ↔ MemLp g p ν := ⟨fun hf => h.memLp_snd hf, fun hg => h.symm.memLp_snd hg⟩
theorem
Probability
[ "Mathlib.Probability.Moments.Variance", "Mathlib.MeasureTheory.Function.UniformIntegrable" ]
Mathlib/Probability/IdentDistrib.lean
memLp_iff
null
integrable_snd [NormedAddCommGroup γ] [BorelSpace γ] (h : IdentDistrib f g μ ν) (hf : Integrable f μ) : Integrable g ν := by rw [← memLp_one_iff_integrable] at hf ⊢ exact h.memLp_snd hf
theorem
Probability
[ "Mathlib.Probability.Moments.Variance", "Mathlib.MeasureTheory.Function.UniformIntegrable" ]
Mathlib/Probability/IdentDistrib.lean
integrable_snd
null
integrable_iff [NormedAddCommGroup γ] [BorelSpace γ] (h : IdentDistrib f g μ ν) : Integrable f μ ↔ Integrable g ν := ⟨fun hf => h.integrable_snd hf, fun hg => h.symm.integrable_snd hg⟩
theorem
Probability
[ "Mathlib.Probability.Moments.Variance", "Mathlib.MeasureTheory.Function.UniformIntegrable" ]
Mathlib/Probability/IdentDistrib.lean
integrable_iff
null
protected norm [NormedAddCommGroup γ] [OpensMeasurableSpace γ] (h : IdentDistrib f g μ ν) : IdentDistrib (fun x => ‖f x‖) (fun x => ‖g x‖) μ ν := h.comp measurable_norm
theorem
Probability
[ "Mathlib.Probability.Moments.Variance", "Mathlib.MeasureTheory.Function.UniformIntegrable" ]
Mathlib/Probability/IdentDistrib.lean
norm
null
protected nnnorm [NormedAddCommGroup γ] [OpensMeasurableSpace γ] (h : IdentDistrib f g μ ν) : IdentDistrib (fun x => ‖f x‖₊) (fun x => ‖g x‖₊) μ ν := h.comp measurable_nnnorm
theorem
Probability
[ "Mathlib.Probability.Moments.Variance", "Mathlib.MeasureTheory.Function.UniformIntegrable" ]
Mathlib/Probability/IdentDistrib.lean
nnnorm
null
protected pow [Pow γ ℕ] [MeasurablePow γ ℕ] (h : IdentDistrib f g μ ν) {n : ℕ} : IdentDistrib (fun x => f x ^ n) (fun x => g x ^ n) μ ν := h.comp (measurable_id.pow_const n)
theorem
Probability
[ "Mathlib.Probability.Moments.Variance", "Mathlib.MeasureTheory.Function.UniformIntegrable" ]
Mathlib/Probability/IdentDistrib.lean
pow
null
protected sq [Pow γ ℕ] [MeasurablePow γ ℕ] (h : IdentDistrib f g μ ν) : IdentDistrib (fun x => f x ^ 2) (fun x => g x ^ 2) μ ν := h.comp (measurable_id.pow_const 2)
theorem
Probability
[ "Mathlib.Probability.Moments.Variance", "Mathlib.MeasureTheory.Function.UniformIntegrable" ]
Mathlib/Probability/IdentDistrib.lean
sq
null
protected coe_nnreal_ennreal {f : α → ℝ≥0} {g : β → ℝ≥0} (h : IdentDistrib f g μ ν) : IdentDistrib (fun x => (f x : ℝ≥0∞)) (fun x => (g x : ℝ≥0∞)) μ ν := h.comp measurable_coe_nnreal_ennreal @[to_additive]
theorem
Probability
[ "Mathlib.Probability.Moments.Variance", "Mathlib.MeasureTheory.Function.UniformIntegrable" ]
Mathlib/Probability/IdentDistrib.lean
coe_nnreal_ennreal
null
mul_const [Mul γ] [MeasurableMul γ] (h : IdentDistrib f g μ ν) (c : γ) : IdentDistrib (fun x => f x * c) (fun x => g x * c) μ ν := h.comp (measurable_mul_const c) @[to_additive]
theorem
Probability
[ "Mathlib.Probability.Moments.Variance", "Mathlib.MeasureTheory.Function.UniformIntegrable" ]
Mathlib/Probability/IdentDistrib.lean
mul_const
null
const_mul [Mul γ] [MeasurableMul γ] (h : IdentDistrib f g μ ν) (c : γ) : IdentDistrib (fun x => c * f x) (fun x => c * g x) μ ν := h.comp (measurable_const_mul c) @[to_additive]
theorem
Probability
[ "Mathlib.Probability.Moments.Variance", "Mathlib.MeasureTheory.Function.UniformIntegrable" ]
Mathlib/Probability/IdentDistrib.lean
const_mul
null
div_const [Div γ] [MeasurableDiv γ] (h : IdentDistrib f g μ ν) (c : γ) : IdentDistrib (fun x => f x / c) (fun x => g x / c) μ ν := h.comp (MeasurableDiv.measurable_div_const c) @[to_additive]
theorem
Probability
[ "Mathlib.Probability.Moments.Variance", "Mathlib.MeasureTheory.Function.UniformIntegrable" ]
Mathlib/Probability/IdentDistrib.lean
div_const
null
const_div [Div γ] [MeasurableDiv γ] (h : IdentDistrib f g μ ν) (c : γ) : IdentDistrib (fun x => c / f x) (fun x => c / g x) μ ν := h.comp (MeasurableDiv.measurable_const_div c) @[to_additive]
theorem
Probability
[ "Mathlib.Probability.Moments.Variance", "Mathlib.MeasureTheory.Function.UniformIntegrable" ]
Mathlib/Probability/IdentDistrib.lean
const_div
null
inv [Inv γ] [MeasurableInv γ] (h : IdentDistrib f g μ ν) : IdentDistrib f⁻¹ g⁻¹ μ ν := h.comp measurable_inv
lemma
Probability
[ "Mathlib.Probability.Moments.Variance", "Mathlib.MeasureTheory.Function.UniformIntegrable" ]
Mathlib/Probability/IdentDistrib.lean
inv
null
evariance_eq {f : α → ℝ} {g : β → ℝ} (h : IdentDistrib f g μ ν) : evariance f μ = evariance g ν := by convert (h.sub_const (∫ x, f x ∂μ)).nnnorm.coe_nnreal_ennreal.sq.lintegral_eq rw [h.integral_eq] rfl
theorem
Probability
[ "Mathlib.Probability.Moments.Variance", "Mathlib.MeasureTheory.Function.UniformIntegrable" ]
Mathlib/Probability/IdentDistrib.lean
evariance_eq
null
variance_eq {f : α → ℝ} {g : β → ℝ} (h : IdentDistrib f g μ ν) : variance f μ = variance g ν := by rw [variance, h.evariance_eq]; rfl
theorem
Probability
[ "Mathlib.Probability.Moments.Variance", "Mathlib.MeasureTheory.Function.UniformIntegrable" ]
Mathlib/Probability/IdentDistrib.lean
variance_eq
null
MemLp.uniformIntegrable_of_identDistrib_aux {ι : Type*} {f : ι → α → E} {j : ι} {p : ℝ≥0∞} (hp : 1 ≤ p) (hp' : p ≠ ∞) (hℒp : MemLp (f j) p μ) (hfmeas : ∀ i, StronglyMeasurable (f i)) (hf : ∀ i, IdentDistrib (f i) (f j) μ μ) : UniformIntegrable f p μ := by refine uniformIntegrable_of' hp hp' hfmeas fun ε hε =>...
theorem
Probability
[ "Mathlib.Probability.Moments.Variance", "Mathlib.MeasureTheory.Function.UniformIntegrable" ]
Mathlib/Probability/IdentDistrib.lean
MemLp.uniformIntegrable_of_identDistrib_aux
This lemma is superseded by `MemLp.uniformIntegrable_of_identDistrib` which only requires `AEStronglyMeasurable`.
MemLp.uniformIntegrable_of_identDistrib {ι : Type*} {f : ι → α → E} {j : ι} {p : ℝ≥0∞} (hp : 1 ≤ p) (hp' : p ≠ ∞) (hℒp : MemLp (f j) p μ) (hf : ∀ i, IdentDistrib (f i) (f j) μ μ) : UniformIntegrable f p μ := by have hfmeas : ∀ i, AEStronglyMeasurable (f i) μ := fun i => (hf i).aestronglyMeasurable_iff.2 h...
theorem
Probability
[ "Mathlib.Probability.Moments.Variance", "Mathlib.MeasureTheory.Function.UniformIntegrable" ]
Mathlib/Probability/IdentDistrib.lean
MemLp.uniformIntegrable_of_identDistrib
A sequence of identically distributed Lᵖ functions is p-uniformly integrable.
indepFun_of_identDistrib_pair {μ : Measure γ} {μ' : Measure δ} [IsFiniteMeasure μ] [IsFiniteMeasure μ'] {X : γ → α} {X' : δ → α} {Y : γ → β} {Y' : δ → β} (h_indep : IndepFun X Y μ) (h_ident : IdentDistrib (fun ω ↦ (X ω, Y ω)) (fun ω ↦ (X' ω, Y' ω)) μ μ') : IndepFun X' Y' μ' := by rw [indepFun_iff_map_...
lemma
Probability
[ "Mathlib.Probability.Moments.Variance", "Mathlib.MeasureTheory.Function.UniformIntegrable" ]
Mathlib/Probability/IdentDistrib.lean
indepFun_of_identDistrib_pair
If `X` and `Y` are independent and `(X, Y)` and `(X', Y')` are identically distributed, then `X'` and `Y'` are independent.
to construct the measure over a product indexed by `ℕ`, which is `infinitePiNat`. This is an implementation detail and should not be used directly. Then we construct the product measure over an arbitrary type by extending `piContent μ` thanks to Carathéodory's theorem. The key lemma to do so is `piContent_tendsto_zero`...
theorem
Probability
[ "Mathlib.Probability.Kernel.Composition.MeasureComp", "Mathlib.Probability.Kernel.IonescuTulcea.Traj" ]
Mathlib/Probability/ProductMeasure.lean
to
null
isProjectiveMeasureFamily_pi : IsProjectiveMeasureFamily (fun I : Finset ι ↦ (Measure.pi (fun i : I ↦ μ i))) := by refine fun I J hJI ↦ Measure.pi_eq (fun s ms ↦ ?_) classical simp_rw [Measure.map_apply (measurable_restrict₂ hJI) (.univ_pi ms), restrict₂_preimage hJI, Measure.pi_pi, prod_eq_prod_extend] ...
lemma
Probability
[ "Mathlib.Probability.Kernel.Composition.MeasureComp", "Mathlib.Probability.Kernel.IonescuTulcea.Traj" ]
Mathlib/Probability/ProductMeasure.lean
isProjectiveMeasureFamily_pi
Consider a family of probability measures. You can take their products for any finite subfamily. This gives a projective family of measures.
noncomputable piContent : AddContent (measurableCylinders X) := projectiveFamilyContent (isProjectiveMeasureFamily_pi μ)
def
Probability
[ "Mathlib.Probability.Kernel.Composition.MeasureComp", "Mathlib.Probability.Kernel.IonescuTulcea.Traj" ]
Mathlib/Probability/ProductMeasure.lean
piContent
Consider a family of probability measures. You can take their products for any finite subfamily. This gives an additive content on the measurable cylinders.
piContent_cylinder {I : Finset ι} {S : Set (Π i : I, X i)} (hS : MeasurableSet S) : piContent μ (cylinder I S) = Measure.pi (fun i : I ↦ μ i) S := projectiveFamilyContent_cylinder _ hS
lemma
Probability
[ "Mathlib.Probability.Kernel.Composition.MeasureComp", "Mathlib.Probability.Kernel.IonescuTulcea.Traj" ]
Mathlib/Probability/ProductMeasure.lean
piContent_cylinder
null
piContent_eq_measure_pi [Fintype ι] {s : Set (Π i, X i)} (hs : MeasurableSet s) : piContent μ s = Measure.pi μ s := by let e : @Finset.univ ι _ ≃ ι := { toFun i := i invFun i := ⟨i, mem_univ i⟩ } have : s = cylinder univ (MeasurableEquiv.piCongrLeft X e ⁻¹' s) := rfl nth_rw 1 [this] dsimp [e] rw...
theorem
Probability
[ "Mathlib.Probability.Kernel.Composition.MeasureComp", "Mathlib.Probability.Kernel.IonescuTulcea.Traj" ]
Mathlib/Probability/ProductMeasure.lean
piContent_eq_measure_pi
null
noncomputable infinitePiNat : Measure (Π n, X n) := (traj (fun n ↦ const _ (μ (n + 1))) 0) ∘ₘ (Measure.pi (fun i : Iic 0 ↦ μ i))
def
Probability
[ "Mathlib.Probability.Kernel.Composition.MeasureComp", "Mathlib.Probability.Kernel.IonescuTulcea.Traj" ]
Mathlib/Probability/ProductMeasure.lean
infinitePiNat
Infinite product measure indexed by `ℕ`. This is an auxiliary construction, you should use the generic product measure `Measure.infinitePi`.
pi_prod_map_IocProdIoc {a b c : ℕ} (hab : a ≤ b) (hbc : b ≤ c) : ((Measure.pi (fun i : Ioc a b ↦ μ i)).prod (Measure.pi (fun i : Ioc b c ↦ μ i))).map (IocProdIoc a b c) = Measure.pi (fun i : Ioc a c ↦ μ i) := by refine (Measure.pi_eq fun s ms ↦ ?_).symm simp_rw [Measure.map_apply measurable_IocProdIoc (.u...
lemma
Probability
[ "Mathlib.Probability.Kernel.Composition.MeasureComp", "Mathlib.Probability.Kernel.IonescuTulcea.Traj" ]
Mathlib/Probability/ProductMeasure.lean
pi_prod_map_IocProdIoc
Let `μ : (i : Ioc a c) → Measure (X i)` be a family of measures. Up to an equivalence, `(⨂ i : Ioc a b, μ i) ⊗ (⨂ i : Ioc b c, μ i) = ⨂ i : Ioc a c, μ i`, where `⊗` denotes the product of measures.
pi_prod_map_IicProdIoc {a b : ℕ} : ((Measure.pi (fun i : Iic a ↦ μ i)).prod (Measure.pi (fun i : Ioc a b ↦ μ i))).map (IicProdIoc a b) = Measure.pi (fun i : Iic b ↦ μ i) := by obtain hab | hba := le_total a b · refine (Measure.pi_eq fun s ms ↦ ?_).symm simp_rw [Measure.map_apply measurable_IicProdIoc ...
lemma
Probability
[ "Mathlib.Probability.Kernel.Composition.MeasureComp", "Mathlib.Probability.Kernel.IonescuTulcea.Traj" ]
Mathlib/Probability/ProductMeasure.lean
pi_prod_map_IicProdIoc
Let `μ : (i : Iic b) → Measure (X i)` be a family of measures. Up to an equivalence, `(⨂ i : Iic a, μ i) ⊗ (⨂ i : Ioc a b, μ i) = ⨂ i : Iic b, μ i`, where `⊗` denotes the product of measures.
map_piSingleton (μ : (n : ℕ) → Measure (X n)) [∀ n, SigmaFinite (μ n)] (n : ℕ) : (μ (n + 1)).map (piSingleton n) = Measure.pi (fun i : Ioc n (n + 1) ↦ μ i) := by refine (Measure.pi_eq fun s hs ↦ ?_).symm have : Subsingleton (Ioc n (n + 1)) := by rw [Nat.Ioc_succ_singleton]; infer_instance rw [Fintype.prod_sub...
lemma
Probability
[ "Mathlib.Probability.Kernel.Composition.MeasureComp", "Mathlib.Probability.Kernel.IonescuTulcea.Traj" ]
Mathlib/Probability/ProductMeasure.lean
map_piSingleton
Let `μ (i + 1) : Measure (X (i + 1))` be a measure. Up to an equivalence, `μ i = ⨂ j : Ioc i (i + 1), μ i`, where `⊗` denotes the product of measures.
partialTraj_const_restrict₂ {a b : ℕ} : (partialTraj (fun n ↦ const _ (μ (n + 1))) a b).map (restrict₂ Ioc_subset_Iic_self) = const _ (Measure.pi (fun i : Ioc a b ↦ μ i)) := by obtain hab | hba := lt_or_ge a b · refine Nat.le_induction ?_ (fun n hn hind ↦ ?_) b (Nat.succ_le.2 hab) <;> ext1 x₀ · rw [part...
theorem
Probability
[ "Mathlib.Probability.Kernel.Composition.MeasureComp", "Mathlib.Probability.Kernel.IonescuTulcea.Traj" ]
Mathlib/Probability/ProductMeasure.lean
partialTraj_const_restrict₂
`partialTraj κ a b` is a kernel which up to an equivalence is equal to `Kernel.id ×ₖ (κ a ⊗ₖ ... ⊗ₖ κ (b - 1))`. This lemma therefore states that if the kernels `κ` are constant then their composition-product is the product measure.
partialTraj_const {a b : ℕ} : partialTraj (fun n ↦ const _ (μ (n + 1))) a b = (Kernel.id ×ₖ (const _ (Measure.pi (fun i : Ioc a b ↦ μ i)))).map (IicProdIoc a b) := by rw [partialTraj_eq_prod, partialTraj_const_restrict₂]
theorem
Probability
[ "Mathlib.Probability.Kernel.Composition.MeasureComp", "Mathlib.Probability.Kernel.IonescuTulcea.Traj" ]
Mathlib/Probability/ProductMeasure.lean
partialTraj_const
`partialTraj κ a b` is a kernel which up to an equivalence is equal to `Kernel.id ×ₖ (κ a ⊗ₖ ... ⊗ₖ κ (b - 1))`. This lemma therefore states that if the kernel `κ i` is constant equal to `μ i` for all `i`, then up to an equivalence `partialTraj κ a b = Kernel.id ×ₖ Kernel.const (⨂ μ i)`.
isProjectiveLimit_infinitePiNat : IsProjectiveLimit (infinitePiNat μ) (fun I : Finset ℕ ↦ (Measure.pi (fun i : I ↦ μ i))) := by intro I rw [isProjectiveMeasureFamily_pi μ _ _ I.subset_Iic_sup_id, ← restrict₂_comp_restrict I.subset_Iic_sup_id, ← map_map, ← frestrictLe, infinitePiNat, map_comp, traj_map_f...
theorem
Probability
[ "Mathlib.Probability.Kernel.Composition.MeasureComp", "Mathlib.Probability.Kernel.IonescuTulcea.Traj" ]
Mathlib/Probability/ProductMeasure.lean
isProjectiveLimit_infinitePiNat
null
infinitePiNat_map_restrict (I : Finset ℕ) : (infinitePiNat μ).map I.restrict = Measure.pi fun i : I ↦ μ i := isProjectiveLimit_infinitePiNat μ I
lemma
Probability
[ "Mathlib.Probability.Kernel.Composition.MeasureComp", "Mathlib.Probability.Kernel.IonescuTulcea.Traj" ]
Mathlib/Probability/ProductMeasure.lean
infinitePiNat_map_restrict
Restricting the product measure to a product indexed by a finset yields the usual product measure.
piContent_eq_infinitePiNat {A : Set (Π n, X n)} (hA : A ∈ measurableCylinders X) : piContent μ A = infinitePiNat μ A := by obtain ⟨s, S, mS, rfl⟩ : ∃ s S, MeasurableSet S ∧ A = cylinder s S := by simpa [mem_measurableCylinders] using hA rw [piContent_cylinder _ mS, cylinder, ← map_apply (measurable_restrict...
theorem
Probability
[ "Mathlib.Probability.Kernel.Composition.MeasureComp", "Mathlib.Probability.Kernel.IonescuTulcea.Traj" ]
Mathlib/Probability/ProductMeasure.lean
piContent_eq_infinitePiNat
null
Measure.infinitePiNat_map_piCongrLeft (e : ℕ ≃ ι) {s : Set (Π i, X i)} (hs : s ∈ measurableCylinders X) : (infinitePiNat (fun n ↦ μ (e n))).map (piCongrLeft X e) s = piContent μ s := by obtain ⟨I, S, hS, rfl⟩ := (mem_measurableCylinders s).1 hs rw [map_apply _ hS.cylinder, cylinder, ← Set.preimage_comp, coe...
lemma
Probability
[ "Mathlib.Probability.Kernel.Composition.MeasureComp", "Mathlib.Probability.Kernel.IonescuTulcea.Traj" ]
Mathlib/Probability/ProductMeasure.lean
Measure.infinitePiNat_map_piCongrLeft
If we push the product measure forward by a reindexing equivalence, we get a product measure on the reindexed product in the sense that it coincides with `piContent μ` over measurable cylinders. See `infinitePi_map_piCongrLeft` for a general version.
piContent_tendsto_zero {A : ℕ → Set (Π i, X i)} (A_mem : ∀ n, A n ∈ measurableCylinders X) (A_anti : Antitone A) (A_inter : ⋂ n, A n = ∅) : Tendsto (fun n ↦ piContent μ (A n)) atTop (𝓝 0) := by have : ∀ i, Nonempty (X i) := fun i ↦ ProbabilityMeasure.nonempty ⟨μ i, hμ i⟩ have A_cyl n : ∃ s S, MeasurableSet...
theorem
Probability
[ "Mathlib.Probability.Kernel.Composition.MeasureComp", "Mathlib.Probability.Kernel.IonescuTulcea.Traj" ]
Mathlib/Probability/ProductMeasure.lean
piContent_tendsto_zero
This is the key theorem to build the product of an arbitrary family of probability measures: the `piContent` of a decreasing sequence of cylinders with empty intersection converges to `0`. This implies the `σ`-additivity of `piContent` (see `addContent_iUnion_eq_sum_of_tendsto_zero`), which allows to extend it to the ...
isSigmaSubadditive_piContent : (piContent μ).IsSigmaSubadditive := by refine isSigmaSubadditive_of_addContent_iUnion_eq_tsum isSetRing_measurableCylinders (fun f hf hf_Union hf' ↦ ?_) exact addContent_iUnion_eq_sum_of_tendsto_zero isSetRing_measurableCylinders (piContent μ) (fun s hs ↦ projectiveFamilyConte...
theorem
Probability
[ "Mathlib.Probability.Kernel.Composition.MeasureComp", "Mathlib.Probability.Kernel.IonescuTulcea.Traj" ]
Mathlib/Probability/ProductMeasure.lean
isSigmaSubadditive_piContent
The `projectiveFamilyContent` associated to a family of probability measures is σ-subadditive.
noncomputable infinitePi : Measure (Π i, X i) := (piContent μ).measure isSetSemiring_measurableCylinders generateFrom_measurableCylinders.ge (isSigmaSubadditive_piContent μ)
def
Probability
[ "Mathlib.Probability.Kernel.Composition.MeasureComp", "Mathlib.Probability.Kernel.IonescuTulcea.Traj" ]
Mathlib/Probability/ProductMeasure.lean
infinitePi
The product measure of an arbitrary family of probability measures. It is defined as the unique extension of the function which gives to cylinders the measure given by the associated product measure.
isProjectiveLimit_infinitePi : IsProjectiveLimit (infinitePi μ) (fun I : Finset ι ↦ (Measure.pi (fun i : I ↦ μ i))) := by intro I ext s hs rw [map_apply (measurable_restrict I) hs, infinitePi, AddContent.measure_eq, ← cylinder, piContent_cylinder μ hs] · exact generateFrom_measurableCylinders.symm · e...
theorem
Probability
[ "Mathlib.Probability.Kernel.Composition.MeasureComp", "Mathlib.Probability.Kernel.IonescuTulcea.Traj" ]
Mathlib/Probability/ProductMeasure.lean
isProjectiveLimit_infinitePi
The product measure is the projective limit of the partial product measures. This ensures uniqueness and expresses the value of the product measure applied to cylinders.
infinitePi_map_restrict {I : Finset ι} : (Measure.infinitePi μ).map I.restrict = Measure.pi fun i : I ↦ μ i := isProjectiveLimit_infinitePi μ I
theorem
Probability
[ "Mathlib.Probability.Kernel.Composition.MeasureComp", "Mathlib.Probability.Kernel.IonescuTulcea.Traj" ]
Mathlib/Probability/ProductMeasure.lean
infinitePi_map_restrict
Restricting the product measure to a product indexed by a finset yields the usual product measure.
eq_infinitePi {ν : Measure (Π i, X i)} (hν : ∀ s : Finset ι, ∀ t : (i : ι) → Set (X i), (∀ i ∈ s, MeasurableSet (t i)) → ν (Set.pi s t) = ∏ i ∈ s, μ i (t i)) : ν = infinitePi μ := by refine (isProjectiveLimit_infinitePi μ).unique ?_ |>.symm refine fun s ↦ (pi_eq fun t ht ↦ ?_).symm classical rw [M...
theorem
Probability
[ "Mathlib.Probability.Kernel.Composition.MeasureComp", "Mathlib.Probability.Kernel.IonescuTulcea.Traj" ]
Mathlib/Probability/ProductMeasure.lean
eq_infinitePi
To prove that a measure is equal to the product measure it is enough to check that it it gives the same measure to measurable boxes.
infinitePi_pi {s : Finset ι} {t : (i : ι) → Set (X i)} (mt : ∀ i ∈ s, MeasurableSet (t i)) : infinitePi μ (Set.pi s t) = ∏ i ∈ s, (μ i) (t i) := by have : Set.pi s t = cylinder s ((@Set.univ s).pi (fun i : s ↦ t i)) := by ext x simp rw [this, cylinder, ← map_apply, infinitePi_map_restrict, pi_pi] ...
lemma
Probability
[ "Mathlib.Probability.Kernel.Composition.MeasureComp", "Mathlib.Probability.Kernel.IonescuTulcea.Traj" ]
Mathlib/Probability/ProductMeasure.lean
infinitePi_pi
null
_root_.measurePreserving_eval_infinitePi (i : ι) : MeasurePreserving (Function.eval i) (infinitePi μ) (μ i) where measurable := by fun_prop map_eq := by ext s hs have : @Function.eval ι X i = (@Function.eval ({i} : Finset ι) (fun j ↦ X j) ⟨i, by simp⟩) ∘ (Finset.restrict {i}) := by ext; ...
lemma
Probability
[ "Mathlib.Probability.Kernel.Composition.MeasureComp", "Mathlib.Probability.Kernel.IonescuTulcea.Traj" ]
Mathlib/Probability/ProductMeasure.lean
_root_.measurePreserving_eval_infinitePi
null
infinitePi_map_pi {Y : ι → Type*} [∀ i, MeasurableSpace (Y i)] {f : (i : ι) → X i → Y i} (hf : ∀ i, Measurable (f i)) : haveI (i : ι) : IsProbabilityMeasure ((μ i).map (f i)) := isProbabilityMeasure_map (hf i).aemeasurable (infinitePi μ).map (fun x i ↦ f i (x i)) = infinitePi (fun i ↦ (μ i).map (f i))...
lemma
Probability
[ "Mathlib.Probability.Kernel.Composition.MeasureComp", "Mathlib.Probability.Kernel.IonescuTulcea.Traj" ]
Mathlib/Probability/ProductMeasure.lean
infinitePi_map_pi
null
infinitePi_map_piCongrLeft {α : Type*} (e : α ≃ ι) : (infinitePi (fun i ↦ μ (e i))).map (piCongrLeft X e) = infinitePi μ := by refine eq_infinitePi μ fun s t ht ↦ ?_ conv_lhs => enter [2, 1]; rw [← e.image_preimage s, ← coe_preimage _ e.injective.injOn] rw [map_apply, coe_piCongrLeft, Equiv.piCongrLeft_preima...
theorem
Probability
[ "Mathlib.Probability.Kernel.Composition.MeasureComp", "Mathlib.Probability.Kernel.IonescuTulcea.Traj" ]
Mathlib/Probability/ProductMeasure.lean
infinitePi_map_piCongrLeft
If we push the product measure forward by a reindexing equivalence, we get a product measure on the reindexed product.
infinitePi_eq_pi [Fintype ι] : infinitePi μ = Measure.pi μ := by refine (pi_eq fun s hs ↦ ?_).symm rw [← coe_univ, infinitePi_pi] simpa
theorem
Probability
[ "Mathlib.Probability.Kernel.Composition.MeasureComp", "Mathlib.Probability.Kernel.IonescuTulcea.Traj" ]
Mathlib/Probability/ProductMeasure.lean
infinitePi_eq_pi
null
infinitePi_cylinder {s : Finset ι} {S : Set (Π i : s, X i)} (mS : MeasurableSet S) : infinitePi μ (cylinder s S) = Measure.pi (fun i : s ↦ μ i) S := by rw [cylinder, ← Measure.map_apply (measurable_restrict _) mS, infinitePi_map_restrict]
lemma
Probability
[ "Mathlib.Probability.Kernel.Composition.MeasureComp", "Mathlib.Probability.Kernel.IonescuTulcea.Traj" ]
Mathlib/Probability/ProductMeasure.lean
infinitePi_cylinder
null
integral_restrict_infinitePi {E : Type*} [NormedAddCommGroup E] [NormedSpace ℝ E] {s : Finset ι} {f : (Π i : s, X i) → E} (hf : AEStronglyMeasurable f (Measure.pi (fun i : s ↦ μ i))) : ∫ y, f (s.restrict y) ∂infinitePi μ = ∫ y, f y ∂Measure.pi (fun i : s ↦ μ i) := by rw [← integral_map, infinitePi_map_res...
theorem
Probability
[ "Mathlib.Probability.Kernel.Composition.MeasureComp", "Mathlib.Probability.Kernel.IonescuTulcea.Traj" ]
Mathlib/Probability/ProductMeasure.lean
integral_restrict_infinitePi
null
lintegral_restrict_infinitePi {s : Finset ι} {f : (Π i : s, X i) → ℝ≥0∞} (hf : Measurable f) : ∫⁻ y, f (s.restrict y) ∂infinitePi μ = ∫⁻ y, f y ∂Measure.pi (fun i : s ↦ μ i) := by rw [← lintegral_map hf (measurable_restrict _), isProjectiveLimit_infinitePi μ] open Filtration
theorem
Probability
[ "Mathlib.Probability.Kernel.Composition.MeasureComp", "Mathlib.Probability.Kernel.IonescuTulcea.Traj" ]
Mathlib/Probability/ProductMeasure.lean
lintegral_restrict_infinitePi
null
integral_infinitePi_of_piFinset [DecidableEq ι] {E : Type*} [NormedAddCommGroup E] [NormedSpace ℝ E] {s : Finset ι} {f : (Π i, X i) → E} (mf : StronglyMeasurable[piFinset s] f) (x : Π i, X i) : ∫ y, f y ∂infinitePi μ = ∫ y, f (Function.updateFinset x s y) ∂Measure.pi (fun i : s ↦ μ i) := by let g : (Π...
theorem
Probability
[ "Mathlib.Probability.Kernel.Composition.MeasureComp", "Mathlib.Probability.Kernel.IonescuTulcea.Traj" ]
Mathlib/Probability/ProductMeasure.lean
integral_infinitePi_of_piFinset
null
lintegral_infinitePi_of_piFinset [DecidableEq ι] {s : Finset ι} {f : (Π i, X i) → ℝ≥0∞} (mf : Measurable[piFinset s] f) (x : Π i, X i) : ∫⁻ y, f y ∂infinitePi μ = (∫⋯∫⁻_s, f ∂μ) x := by let g : (Π i : s, X i) → ℝ≥0∞ := fun y ↦ f (Function.updateFinset x _ y) have this y : g (s.restrict y) = f y := mf.de...
theorem
Probability
[ "Mathlib.Probability.Kernel.Composition.MeasureComp", "Mathlib.Probability.Kernel.IonescuTulcea.Traj" ]
Mathlib/Probability/ProductMeasure.lean
lintegral_infinitePi_of_piFinset
null
truncation (f : α → ℝ) (A : ℝ) := indicator (Set.Ioc (-A) A) id ∘ f variable {m : MeasurableSpace α} {μ : Measure α} {f : α → ℝ}
def
Probability
[ "Mathlib.Probability.IdentDistrib", "Mathlib.Probability.Independence.Integrable", "Mathlib.MeasureTheory.Integral.DominatedConvergence", "Mathlib.Analysis.SpecificLimits.FloorPow", "Mathlib.Analysis.PSeries", "Mathlib.Analysis.Asymptotics.SpecificAsymptotics" ]
Mathlib/Probability/StrongLaw.lean
truncation
Truncating a real-valued function to the interval `(-A, A]`.
_root_.MeasureTheory.AEStronglyMeasurable.truncation (hf : AEStronglyMeasurable f μ) {A : ℝ} : AEStronglyMeasurable (truncation f A) μ := by apply AEStronglyMeasurable.comp_aemeasurable _ hf.aemeasurable exact (stronglyMeasurable_id.indicator measurableSet_Ioc).aestronglyMeasurable
theorem
Probability
[ "Mathlib.Probability.IdentDistrib", "Mathlib.Probability.Independence.Integrable", "Mathlib.MeasureTheory.Integral.DominatedConvergence", "Mathlib.Analysis.SpecificLimits.FloorPow", "Mathlib.Analysis.PSeries", "Mathlib.Analysis.Asymptotics.SpecificAsymptotics" ]
Mathlib/Probability/StrongLaw.lean
_root_.MeasureTheory.AEStronglyMeasurable.truncation
null
abs_truncation_le_bound (f : α → ℝ) (A : ℝ) (x : α) : |truncation f A x| ≤ |A| := by simp only [truncation, Set.indicator, id, Function.comp_apply] split_ifs with h · exact abs_le_abs h.2 (neg_le.2 h.1.le) · simp [abs_nonneg] @[simp]
theorem
Probability
[ "Mathlib.Probability.IdentDistrib", "Mathlib.Probability.Independence.Integrable", "Mathlib.MeasureTheory.Integral.DominatedConvergence", "Mathlib.Analysis.SpecificLimits.FloorPow", "Mathlib.Analysis.PSeries", "Mathlib.Analysis.Asymptotics.SpecificAsymptotics" ]
Mathlib/Probability/StrongLaw.lean
abs_truncation_le_bound
null
truncation_zero (f : α → ℝ) : truncation f 0 = 0 := by simp [truncation]; rfl
theorem
Probability
[ "Mathlib.Probability.IdentDistrib", "Mathlib.Probability.Independence.Integrable", "Mathlib.MeasureTheory.Integral.DominatedConvergence", "Mathlib.Analysis.SpecificLimits.FloorPow", "Mathlib.Analysis.PSeries", "Mathlib.Analysis.Asymptotics.SpecificAsymptotics" ]
Mathlib/Probability/StrongLaw.lean
truncation_zero
null
abs_truncation_le_abs_self (f : α → ℝ) (A : ℝ) (x : α) : |truncation f A x| ≤ |f x| := by simp only [truncation, indicator, id, Function.comp_apply] split_ifs · exact le_rfl · simp [abs_nonneg]
theorem
Probability
[ "Mathlib.Probability.IdentDistrib", "Mathlib.Probability.Independence.Integrable", "Mathlib.MeasureTheory.Integral.DominatedConvergence", "Mathlib.Analysis.SpecificLimits.FloorPow", "Mathlib.Analysis.PSeries", "Mathlib.Analysis.Asymptotics.SpecificAsymptotics" ]
Mathlib/Probability/StrongLaw.lean
abs_truncation_le_abs_self
null
truncation_eq_self {f : α → ℝ} {A : ℝ} {x : α} (h : |f x| < A) : truncation f A x = f x := by simp only [truncation, indicator, id, Function.comp_apply, ite_eq_left_iff] intro H apply H.elim simp [(abs_lt.1 h).1, (abs_lt.1 h).2.le]
theorem
Probability
[ "Mathlib.Probability.IdentDistrib", "Mathlib.Probability.Independence.Integrable", "Mathlib.MeasureTheory.Integral.DominatedConvergence", "Mathlib.Analysis.SpecificLimits.FloorPow", "Mathlib.Analysis.PSeries", "Mathlib.Analysis.Asymptotics.SpecificAsymptotics" ]
Mathlib/Probability/StrongLaw.lean
truncation_eq_self
null
truncation_eq_of_nonneg {f : α → ℝ} {A : ℝ} (h : ∀ x, 0 ≤ f x) : truncation f A = indicator (Set.Ioc 0 A) id ∘ f := by ext x rcases (h x).lt_or_eq with (hx | hx) · simp only [truncation, indicator, hx, Set.mem_Ioc, id, Function.comp_apply] by_cases h'x : f x ≤ A · have : -A < f x := by linarith [h x] ...
theorem
Probability
[ "Mathlib.Probability.IdentDistrib", "Mathlib.Probability.Independence.Integrable", "Mathlib.MeasureTheory.Integral.DominatedConvergence", "Mathlib.Analysis.SpecificLimits.FloorPow", "Mathlib.Analysis.PSeries", "Mathlib.Analysis.Asymptotics.SpecificAsymptotics" ]
Mathlib/Probability/StrongLaw.lean
truncation_eq_of_nonneg
null
truncation_nonneg {f : α → ℝ} (A : ℝ) {x : α} (h : 0 ≤ f x) : 0 ≤ truncation f A x := Set.indicator_apply_nonneg fun _ => h
theorem
Probability
[ "Mathlib.Probability.IdentDistrib", "Mathlib.Probability.Independence.Integrable", "Mathlib.MeasureTheory.Integral.DominatedConvergence", "Mathlib.Analysis.SpecificLimits.FloorPow", "Mathlib.Analysis.PSeries", "Mathlib.Analysis.Asymptotics.SpecificAsymptotics" ]
Mathlib/Probability/StrongLaw.lean
truncation_nonneg
null
_root_.MeasureTheory.AEStronglyMeasurable.memLp_truncation [IsFiniteMeasure μ] (hf : AEStronglyMeasurable f μ) {A : ℝ} {p : ℝ≥0∞} : MemLp (truncation f A) p μ := MemLp.of_bound hf.truncation |A| (Eventually.of_forall fun _ => abs_truncation_le_bound _ _ _)
theorem
Probability
[ "Mathlib.Probability.IdentDistrib", "Mathlib.Probability.Independence.Integrable", "Mathlib.MeasureTheory.Integral.DominatedConvergence", "Mathlib.Analysis.SpecificLimits.FloorPow", "Mathlib.Analysis.PSeries", "Mathlib.Analysis.Asymptotics.SpecificAsymptotics" ]
Mathlib/Probability/StrongLaw.lean
_root_.MeasureTheory.AEStronglyMeasurable.memLp_truncation
null
_root_.MeasureTheory.AEStronglyMeasurable.integrable_truncation [IsFiniteMeasure μ] (hf : AEStronglyMeasurable f μ) {A : ℝ} : Integrable (truncation f A) μ := by rw [← memLp_one_iff_integrable]; exact hf.memLp_truncation
theorem
Probability
[ "Mathlib.Probability.IdentDistrib", "Mathlib.Probability.Independence.Integrable", "Mathlib.MeasureTheory.Integral.DominatedConvergence", "Mathlib.Analysis.SpecificLimits.FloorPow", "Mathlib.Analysis.PSeries", "Mathlib.Analysis.Asymptotics.SpecificAsymptotics" ]
Mathlib/Probability/StrongLaw.lean
_root_.MeasureTheory.AEStronglyMeasurable.integrable_truncation
null
moment_truncation_eq_intervalIntegral (hf : AEStronglyMeasurable f μ) {A : ℝ} (hA : 0 ≤ A) {n : ℕ} (hn : n ≠ 0) : ∫ x, truncation f A x ^ n ∂μ = ∫ y in -A..A, y ^ n ∂Measure.map f μ := by have M : MeasurableSet (Set.Ioc (-A) A) := measurableSet_Ioc change ∫ x, (fun z => indicator (Set.Ioc (-A) A) id z ^ n) (f x...
theorem
Probability
[ "Mathlib.Probability.IdentDistrib", "Mathlib.Probability.Independence.Integrable", "Mathlib.MeasureTheory.Integral.DominatedConvergence", "Mathlib.Analysis.SpecificLimits.FloorPow", "Mathlib.Analysis.PSeries", "Mathlib.Analysis.Asymptotics.SpecificAsymptotics" ]
Mathlib/Probability/StrongLaw.lean
moment_truncation_eq_intervalIntegral
null
moment_truncation_eq_intervalIntegral_of_nonneg (hf : AEStronglyMeasurable f μ) {A : ℝ} {n : ℕ} (hn : n ≠ 0) (h'f : 0 ≤ f) : ∫ x, truncation f A x ^ n ∂μ = ∫ y in 0..A, y ^ n ∂Measure.map f μ := by have M : MeasurableSet (Set.Ioc 0 A) := measurableSet_Ioc have M' : MeasurableSet (Set.Ioc A 0) := measurableS...
theorem
Probability
[ "Mathlib.Probability.IdentDistrib", "Mathlib.Probability.Independence.Integrable", "Mathlib.MeasureTheory.Integral.DominatedConvergence", "Mathlib.Analysis.SpecificLimits.FloorPow", "Mathlib.Analysis.PSeries", "Mathlib.Analysis.Asymptotics.SpecificAsymptotics" ]
Mathlib/Probability/StrongLaw.lean
moment_truncation_eq_intervalIntegral_of_nonneg
null
integral_truncation_eq_intervalIntegral (hf : AEStronglyMeasurable f μ) {A : ℝ} (hA : 0 ≤ A) : ∫ x, truncation f A x ∂μ = ∫ y in -A..A, y ∂Measure.map f μ := by simpa using moment_truncation_eq_intervalIntegral hf hA one_ne_zero
theorem
Probability
[ "Mathlib.Probability.IdentDistrib", "Mathlib.Probability.Independence.Integrable", "Mathlib.MeasureTheory.Integral.DominatedConvergence", "Mathlib.Analysis.SpecificLimits.FloorPow", "Mathlib.Analysis.PSeries", "Mathlib.Analysis.Asymptotics.SpecificAsymptotics" ]
Mathlib/Probability/StrongLaw.lean
integral_truncation_eq_intervalIntegral
null
integral_truncation_eq_intervalIntegral_of_nonneg (hf : AEStronglyMeasurable f μ) {A : ℝ} (h'f : 0 ≤ f) : ∫ x, truncation f A x ∂μ = ∫ y in 0..A, y ∂Measure.map f μ := by simpa using moment_truncation_eq_intervalIntegral_of_nonneg hf one_ne_zero h'f
theorem
Probability
[ "Mathlib.Probability.IdentDistrib", "Mathlib.Probability.Independence.Integrable", "Mathlib.MeasureTheory.Integral.DominatedConvergence", "Mathlib.Analysis.SpecificLimits.FloorPow", "Mathlib.Analysis.PSeries", "Mathlib.Analysis.Asymptotics.SpecificAsymptotics" ]
Mathlib/Probability/StrongLaw.lean
integral_truncation_eq_intervalIntegral_of_nonneg
null
integral_truncation_le_integral_of_nonneg (hf : Integrable f μ) (h'f : 0 ≤ f) {A : ℝ} : ∫ x, truncation f A x ∂μ ≤ ∫ x, f x ∂μ := by apply integral_mono_of_nonneg (Eventually.of_forall fun x => ?_) hf (Eventually.of_forall fun x => ?_) · exact truncation_nonneg _ (h'f x) · calc truncation f A x ≤ |t...
theorem
Probability
[ "Mathlib.Probability.IdentDistrib", "Mathlib.Probability.Independence.Integrable", "Mathlib.MeasureTheory.Integral.DominatedConvergence", "Mathlib.Analysis.SpecificLimits.FloorPow", "Mathlib.Analysis.PSeries", "Mathlib.Analysis.Asymptotics.SpecificAsymptotics" ]
Mathlib/Probability/StrongLaw.lean
integral_truncation_le_integral_of_nonneg
null
tendsto_integral_truncation {f : α → ℝ} (hf : Integrable f μ) : Tendsto (fun A => ∫ x, truncation f A x ∂μ) atTop (𝓝 (∫ x, f x ∂μ)) := by refine tendsto_integral_filter_of_dominated_convergence (fun x => abs (f x)) ?_ ?_ ?_ ?_ · exact Eventually.of_forall fun A ↦ hf.aestronglyMeasurable.truncation · filter_u...
theorem
Probability
[ "Mathlib.Probability.IdentDistrib", "Mathlib.Probability.Independence.Integrable", "Mathlib.MeasureTheory.Integral.DominatedConvergence", "Mathlib.Analysis.SpecificLimits.FloorPow", "Mathlib.Analysis.PSeries", "Mathlib.Analysis.Asymptotics.SpecificAsymptotics" ]
Mathlib/Probability/StrongLaw.lean
tendsto_integral_truncation
If a function is integrable, then the integral of its truncated versions converges to the integral of the whole function.
IdentDistrib.truncation {β : Type*} [MeasurableSpace β] {ν : Measure β} {f : α → ℝ} {g : β → ℝ} (h : IdentDistrib f g μ ν) {A : ℝ} : IdentDistrib (truncation f A) (truncation g A) μ ν := h.comp (measurable_id.indicator measurableSet_Ioc)
theorem
Probability
[ "Mathlib.Probability.IdentDistrib", "Mathlib.Probability.Independence.Integrable", "Mathlib.MeasureTheory.Integral.DominatedConvergence", "Mathlib.Analysis.SpecificLimits.FloorPow", "Mathlib.Analysis.PSeries", "Mathlib.Analysis.Asymptotics.SpecificAsymptotics" ]
Mathlib/Probability/StrongLaw.lean
IdentDistrib.truncation
null
sum_prob_mem_Ioc_le {X : Ω → ℝ} (hint : Integrable X) (hnonneg : 0 ≤ X) {K : ℕ} {N : ℕ} (hKN : K ≤ N) : ∑ j ∈ range K, ℙ {ω | X ω ∈ Set.Ioc (j : ℝ) N} ≤ ENNReal.ofReal (𝔼[X] + 1) := by let ρ : Measure ℝ := Measure.map X ℙ haveI : IsProbabilityMeasure ρ := Measure.isProbabilityMeasure_map hint.aemeasurable ...
theorem
Probability
[ "Mathlib.Probability.IdentDistrib", "Mathlib.Probability.Independence.Integrable", "Mathlib.MeasureTheory.Integral.DominatedConvergence", "Mathlib.Analysis.SpecificLimits.FloorPow", "Mathlib.Analysis.PSeries", "Mathlib.Analysis.Asymptotics.SpecificAsymptotics" ]
Mathlib/Probability/StrongLaw.lean
sum_prob_mem_Ioc_le
null
tsum_prob_mem_Ioi_lt_top {X : Ω → ℝ} (hint : Integrable X) (hnonneg : 0 ≤ X) : (∑' j : ℕ, ℙ {ω | X ω ∈ Set.Ioi (j : ℝ)}) < ∞ := by suffices ∀ K : ℕ, ∑ j ∈ range K, ℙ {ω | X ω ∈ Set.Ioi (j : ℝ)} ≤ ENNReal.ofReal (𝔼[X] + 1) from (le_of_tendsto_of_tendsto (ENNReal.tendsto_nat_tsum _) tendsto_const_nhds (E...
theorem
Probability
[ "Mathlib.Probability.IdentDistrib", "Mathlib.Probability.Independence.Integrable", "Mathlib.MeasureTheory.Integral.DominatedConvergence", "Mathlib.Analysis.SpecificLimits.FloorPow", "Mathlib.Analysis.PSeries", "Mathlib.Analysis.Asymptotics.SpecificAsymptotics" ]
Mathlib/Probability/StrongLaw.lean
tsum_prob_mem_Ioi_lt_top
null
sum_variance_truncation_le {X : Ω → ℝ} (hint : Integrable X) (hnonneg : 0 ≤ X) (K : ℕ) : ∑ j ∈ range K, ((j : ℝ) ^ 2)⁻¹ * 𝔼[truncation X j ^ 2] ≤ 2 * 𝔼[X] := by set Y := fun n : ℕ => truncation X n let ρ : Measure ℝ := Measure.map X ℙ have Y2 : ∀ n, 𝔼[Y n ^ 2] = ∫ x in 0..n, x ^ 2 ∂ρ := by intro n ...
theorem
Probability
[ "Mathlib.Probability.IdentDistrib", "Mathlib.Probability.Independence.Integrable", "Mathlib.MeasureTheory.Integral.DominatedConvergence", "Mathlib.Analysis.SpecificLimits.FloorPow", "Mathlib.Analysis.PSeries", "Mathlib.Analysis.Asymptotics.SpecificAsymptotics" ]
Mathlib/Probability/StrongLaw.lean
sum_variance_truncation_le
null
strong_law_aux1 {c : ℝ} (c_one : 1 < c) {ε : ℝ} (εpos : 0 < ε) : ∀ᵐ ω, ∀ᶠ n : ℕ in atTop, |∑ i ∈ range ⌊c ^ n⌋₊, truncation (X i) i ω - 𝔼[∑ i ∈ range ⌊c ^ n⌋₊, truncation (X i) i]| < ε * ⌊c ^ n⌋₊ := by /- Let `S n = ∑ i ∈ range n, Y i` where `Y i = truncation (X i) i`. We should show that `|S k - 𝔼[S k]...
theorem
Probability
[ "Mathlib.Probability.IdentDistrib", "Mathlib.Probability.Independence.Integrable", "Mathlib.MeasureTheory.Integral.DominatedConvergence", "Mathlib.Analysis.SpecificLimits.FloorPow", "Mathlib.Analysis.PSeries", "Mathlib.Analysis.Asymptotics.SpecificAsymptotics" ]
Mathlib/Probability/StrongLaw.lean
strong_law_aux1
The truncation of `Xᵢ` up to `i` satisfies the strong law of large numbers (with respect to the truncated expectation) along the sequence `c^n`, for any `c > 1`, up to a given `ε > 0`. This follows from a variance control.
strong_law_aux2 {c : ℝ} (c_one : 1 < c) : ∀ᵐ ω, (fun n : ℕ => ∑ i ∈ range ⌊c ^ n⌋₊, truncation (X i) i ω - 𝔼[∑ i ∈ range ⌊c ^ n⌋₊, truncation (X i) i]) =o[atTop] fun n : ℕ => (⌊c ^ n⌋₊ : ℝ) := by obtain ⟨v, -, v_pos, v_lim⟩ : ∃ v : ℕ → ℝ, StrictAnti v ∧ (∀ n : ℕ, 0 < v n) ∧ Tendsto v atTop (𝓝 0) := ...
theorem
Probability
[ "Mathlib.Probability.IdentDistrib", "Mathlib.Probability.Independence.Integrable", "Mathlib.MeasureTheory.Integral.DominatedConvergence", "Mathlib.Analysis.SpecificLimits.FloorPow", "Mathlib.Analysis.PSeries", "Mathlib.Analysis.Asymptotics.SpecificAsymptotics" ]
Mathlib/Probability/StrongLaw.lean
strong_law_aux2
The truncation of `Xᵢ` up to `i` satisfies the strong law of large numbers (with respect to the truncated expectation) along the sequence `c^n`, for any `c > 1`. This follows from `strong_law_aux1` by varying `ε`.
strong_law_aux3 : (fun n => 𝔼[∑ i ∈ range n, truncation (X i) i] - n * 𝔼[X 0]) =o[atTop] ((↑) : ℕ → ℝ) := by have A : Tendsto (fun i => 𝔼[truncation (X i) i]) atTop (𝓝 𝔼[X 0]) := by convert (tendsto_integral_truncation hint).comp tendsto_natCast_atTop_atTop using 1 ext i exact (hident i).truncati...
theorem
Probability
[ "Mathlib.Probability.IdentDistrib", "Mathlib.Probability.Independence.Integrable", "Mathlib.MeasureTheory.Integral.DominatedConvergence", "Mathlib.Analysis.SpecificLimits.FloorPow", "Mathlib.Analysis.PSeries", "Mathlib.Analysis.Asymptotics.SpecificAsymptotics" ]
Mathlib/Probability/StrongLaw.lean
strong_law_aux3
The expectation of the truncated version of `Xᵢ` behaves asymptotically like the whole expectation. This follows from convergence and Cesàro averaging.
strong_law_aux4 {c : ℝ} (c_one : 1 < c) : ∀ᵐ ω, (fun n : ℕ => ∑ i ∈ range ⌊c ^ n⌋₊, truncation (X i) i ω - ⌊c ^ n⌋₊ * 𝔼[X 0]) =o[atTop] fun n : ℕ => (⌊c ^ n⌋₊ : ℝ) := by filter_upwards [strong_law_aux2 X hint hindep hident hnonneg c_one] with ω hω have A : Tendsto (fun n : ℕ => ⌊c ^ n⌋₊) atTop atTop := ...
theorem
Probability
[ "Mathlib.Probability.IdentDistrib", "Mathlib.Probability.Independence.Integrable", "Mathlib.MeasureTheory.Integral.DominatedConvergence", "Mathlib.Analysis.SpecificLimits.FloorPow", "Mathlib.Analysis.PSeries", "Mathlib.Analysis.Asymptotics.SpecificAsymptotics" ]
Mathlib/Probability/StrongLaw.lean
strong_law_aux4
The truncation of `Xᵢ` up to `i` satisfies the strong law of large numbers (with respect to the original expectation) along the sequence `c^n`, for any `c > 1`. This follows from the version from the truncated expectation, and the fact that the truncated and the original expectations have the same asymptotic behavior.
strong_law_aux5 : ∀ᵐ ω, (fun n : ℕ => ∑ i ∈ range n, truncation (X i) i ω - ∑ i ∈ range n, X i ω) =o[atTop] fun n : ℕ => (n : ℝ) := by have A : (∑' j : ℕ, ℙ {ω | X j ω ∈ Set.Ioi (j : ℝ)}) < ∞ := by convert tsum_prob_mem_Ioi_lt_top hint (hnonneg 0) using 2 ext1 j exact (hident j).measure_mem_eq mea...
theorem
Probability
[ "Mathlib.Probability.IdentDistrib", "Mathlib.Probability.Independence.Integrable", "Mathlib.MeasureTheory.Integral.DominatedConvergence", "Mathlib.Analysis.SpecificLimits.FloorPow", "Mathlib.Analysis.PSeries", "Mathlib.Analysis.Asymptotics.SpecificAsymptotics" ]
Mathlib/Probability/StrongLaw.lean
strong_law_aux5
The truncated and non-truncated versions of `Xᵢ` have the same asymptotic behavior, as they almost surely coincide at all but finitely many steps. This follows from a probability computation and Borel-Cantelli.
strong_law_aux6 {c : ℝ} (c_one : 1 < c) : ∀ᵐ ω, Tendsto (fun n : ℕ => (∑ i ∈ range ⌊c ^ n⌋₊, X i ω) / ⌊c ^ n⌋₊) atTop (𝓝 𝔼[X 0]) := by have H : ∀ n : ℕ, (0 : ℝ) < ⌊c ^ n⌋₊ := by intro n refine zero_lt_one.trans_le ?_ simp only [Nat.one_le_cast, Nat.one_le_floor_iff, one_le_pow₀ c_one.le] filter_up...
theorem
Probability
[ "Mathlib.Probability.IdentDistrib", "Mathlib.Probability.Independence.Integrable", "Mathlib.MeasureTheory.Integral.DominatedConvergence", "Mathlib.Analysis.SpecificLimits.FloorPow", "Mathlib.Analysis.PSeries", "Mathlib.Analysis.Asymptotics.SpecificAsymptotics" ]
Mathlib/Probability/StrongLaw.lean
strong_law_aux6
`Xᵢ` satisfies the strong law of large numbers along the sequence `c^n`, for any `c > 1`. This follows from the version for the truncated `Xᵢ`, and the fact that `Xᵢ` and its truncated version have the same asymptotic behavior.
strong_law_aux7 : ∀ᵐ ω, Tendsto (fun n : ℕ => (∑ i ∈ range n, X i ω) / n) atTop (𝓝 𝔼[X 0]) := by obtain ⟨c, -, cone, clim⟩ : ∃ c : ℕ → ℝ, StrictAnti c ∧ (∀ n : ℕ, 1 < c n) ∧ Tendsto c atTop (𝓝 1) := exists_seq_strictAnti_tendsto (1 : ℝ) have : ∀ k, ∀ᵐ ω, Tendsto (fun n : ℕ => (∑ i ∈ range ⌊c ...
theorem
Probability
[ "Mathlib.Probability.IdentDistrib", "Mathlib.Probability.Independence.Integrable", "Mathlib.MeasureTheory.Integral.DominatedConvergence", "Mathlib.Analysis.SpecificLimits.FloorPow", "Mathlib.Analysis.PSeries", "Mathlib.Analysis.Asymptotics.SpecificAsymptotics" ]
Mathlib/Probability/StrongLaw.lean
strong_law_aux7
`Xᵢ` satisfies the strong law of large numbers along all integers. This follows from the corresponding fact along the sequences `c^n`, and the fact that any integer can be sandwiched between `c^n` and `c^(n+1)` with comparably small error if `c` is close enough to `1` (which is formalized in `tendsto_div_of_monotone_of...
strong_law_ae_real {Ω : Type*} {m : MeasurableSpace Ω} {μ : Measure Ω} (X : ℕ → Ω → ℝ) (hint : Integrable (X 0) μ) (hindep : Pairwise ((IndepFun · · μ) on X)) (hident : ∀ i, IdentDistrib (X i) (X 0) μ μ) : ∀ᵐ ω ∂μ, Tendsto (fun n : ℕ => (∑ i ∈ range n, X i ω) / n) atTop (𝓝 μ[X 0]) := by let mΩ : Meas...
theorem
Probability
[ "Mathlib.Probability.IdentDistrib", "Mathlib.Probability.Independence.Integrable", "Mathlib.MeasureTheory.Integral.DominatedConvergence", "Mathlib.Analysis.SpecificLimits.FloorPow", "Mathlib.Analysis.PSeries", "Mathlib.Analysis.Asymptotics.SpecificAsymptotics" ]
Mathlib/Probability/StrongLaw.lean
strong_law_ae_real
**Strong law of large numbers**, almost sure version: if `X n` is a sequence of independent identically distributed integrable real-valued random variables, then `∑ i ∈ range n, X i / n` converges almost surely to `𝔼[X 0]`. We give here the strong version, due to Etemadi, that only requires pairwise independence. Supe...
strong_law_ae_simpleFunc_comp (X : ℕ → Ω → E) (h' : Measurable (X 0)) (hindep : Pairwise ((IndepFun · · μ) on X)) (hident : ∀ i, IdentDistrib (X i) (X 0) μ μ) (φ : SimpleFunc E E) : ∀ᵐ ω ∂μ, Tendsto (fun n : ℕ ↦ (n : ℝ) ⁻¹ • (∑ i ∈ range n, φ (X i ω))) atTop (𝓝 μ[φ ∘ (X 0)]) := by classical refin...
lemma
Probability
[ "Mathlib.Probability.IdentDistrib", "Mathlib.Probability.Independence.Integrable", "Mathlib.MeasureTheory.Integral.DominatedConvergence", "Mathlib.Analysis.SpecificLimits.FloorPow", "Mathlib.Analysis.PSeries", "Mathlib.Analysis.Asymptotics.SpecificAsymptotics" ]
Mathlib/Probability/StrongLaw.lean
strong_law_ae_simpleFunc_comp
Preliminary lemma for the strong law of large numbers for vector-valued random variables: the composition of the random variables with a simple function satisfies the strong law of large numbers.