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indep_supr_limsup (h_le : ∀ n, s n ≤ m0) (h_indep : Indep s μ) (hf : ∀ t, p t → tᶜ ∈ f) (hns : directed (≤) ns) (hnsp : ∀ a, p (ns a)) (hns_univ : ∀ n, ∃ a, n ∈ ns a) : indep (⨆ n, s n) (limsup s f) μ
begin suffices : (⨆ a, ⨆ n ∈ (ns a), s n) = ⨆ n, s n, { rw ← this, exact indep_supr_directed_limsup h_le h_indep hf hns hnsp, }, rw supr_comm, refine supr_congr (λ n, _), have : (⨆ (i : α) (H : n ∈ ns i), s n) = (⨆ (h : ∃ i, n ∈ ns i), s n), by rw supr_exists, haveI : nonempty (∃ (i : α), n ∈ ns i) := ⟨...
lemma
probability_theory.indep_supr_limsup
probability.independence
src/probability/independence/zero_one.lean
[ "probability.independence.basic" ]
[ "directed", "supr_comm", "supr_congr", "supr_const", "supr_exists" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
indep_limsup_self (h_le : ∀ n, s n ≤ m0) (h_indep : Indep s μ) (hf : ∀ t, p t → tᶜ ∈ f) (hns : directed (≤) ns) (hnsp : ∀ a, p (ns a)) (hns_univ : ∀ n, ∃ a, n ∈ ns a) : indep (limsup s f) (limsup s f) μ
indep_of_indep_of_le_left (indep_supr_limsup h_le h_indep hf hns hnsp hns_univ) limsup_le_supr
lemma
probability_theory.indep_limsup_self
probability.independence
src/probability/independence/zero_one.lean
[ "probability.independence.basic" ]
[ "directed" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
measure_zero_or_one_of_measurable_set_limsup (h_le : ∀ n, s n ≤ m0) (h_indep : Indep s μ) (hf : ∀ t, p t → tᶜ ∈ f) (hns : directed (≤) ns) (hnsp : ∀ a, p (ns a)) (hns_univ : ∀ n, ∃ a, n ∈ ns a) {t : set Ω} (ht_tail : measurable_set[limsup s f] t) : μ t = 0 ∨ μ t = 1
measure_eq_zero_or_one_of_indep_set_self ((indep_limsup_self h_le h_indep hf hns hnsp hns_univ).indep_set_of_measurable_set ht_tail ht_tail)
theorem
probability_theory.measure_zero_or_one_of_measurable_set_limsup
probability.independence
src/probability/independence/zero_one.lean
[ "probability.independence.basic" ]
[ "directed", "measurable_set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
indep_limsup_at_top_self (h_le : ∀ n, s n ≤ m0) (h_indep : Indep s μ) : indep (limsup s at_top) (limsup s at_top) μ
begin let ns : ι → set ι := set.Iic, have hnsp : ∀ i, bdd_above (ns i) := λ i, bdd_above_Iic, refine indep_limsup_self h_le h_indep _ _ hnsp _, { simp only [mem_at_top_sets, ge_iff_le, set.mem_compl_iff, bdd_above, upper_bounds, set.nonempty], rintros t ⟨a, ha⟩, obtain ⟨b, hb⟩ : ∃ b, a < b := exis...
lemma
probability_theory.indep_limsup_at_top_self
probability.independence
src/probability/independence/zero_one.lean
[ "probability.independence.basic" ]
[ "bdd_above", "bdd_above_Iic", "ge_iff_le", "monotone.directed_le", "set.Iic", "set.mem_compl_iff", "set.nonempty", "upper_bounds" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
measure_zero_or_one_of_measurable_set_limsup_at_top (h_le : ∀ n, s n ≤ m0) (h_indep : Indep s μ) {t : set Ω} (ht_tail : measurable_set[limsup s at_top] t) : μ t = 0 ∨ μ t = 1
measure_eq_zero_or_one_of_indep_set_self ((indep_limsup_at_top_self h_le h_indep).indep_set_of_measurable_set ht_tail ht_tail)
theorem
probability_theory.measure_zero_or_one_of_measurable_set_limsup_at_top
probability.independence
src/probability/independence/zero_one.lean
[ "probability.independence.basic" ]
[ "measurable_set" ]
**Kolmogorov's 0-1 law** : any event in the tail σ-algebra of an independent sequence of sub-σ-algebras has probability 0 or 1. The tail σ-algebra `limsup s at_top` is the same as `⋂ n, ⋃ i ≥ n, s i`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
indep_limsup_at_bot_self (h_le : ∀ n, s n ≤ m0) (h_indep : Indep s μ) : indep (limsup s at_bot) (limsup s at_bot) μ
begin let ns : ι → set ι := set.Ici, have hnsp : ∀ i, bdd_below (ns i) := λ i, bdd_below_Ici, refine indep_limsup_self h_le h_indep _ _ hnsp _, { simp only [mem_at_bot_sets, ge_iff_le, set.mem_compl_iff, bdd_below, lower_bounds, set.nonempty], rintros t ⟨a, ha⟩, obtain ⟨b, hb⟩ : ∃ b, b < a := exis...
lemma
probability_theory.indep_limsup_at_bot_self
probability.independence
src/probability/independence/zero_one.lean
[ "probability.independence.basic" ]
[ "bdd_below", "bdd_below_Ici", "directed_of_inf", "ge_iff_le", "lower_bounds", "set.Ici", "set.mem_compl_iff", "set.nonempty" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
measure_zero_or_one_of_measurable_set_limsup_at_bot (h_le : ∀ n, s n ≤ m0) (h_indep : Indep s μ) {t : set Ω} (ht_tail : measurable_set[limsup s at_bot] t) : μ t = 0 ∨ μ t = 1
measure_eq_zero_or_one_of_indep_set_self ((indep_limsup_at_bot_self h_le h_indep).indep_set_of_measurable_set ht_tail ht_tail)
theorem
probability_theory.measure_zero_or_one_of_measurable_set_limsup_at_bot
probability.independence
src/probability/independence/zero_one.lean
[ "probability.independence.basic" ]
[ "measurable_set" ]
**Kolmogorov's 0-1 law** : any event in the tail σ-algebra of an independent sequence of sub-σ-algebras has probability 0 or 1.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
kernel (α β : Type*) [measurable_space α] [measurable_space β] : add_submonoid (α → measure β)
{ carrier := measurable, zero_mem' := measurable_zero, add_mem' := λ f g hf hg, measurable.add hf hg, }
def
probability_theory.kernel
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "add_submonoid", "measurable", "measurable_space" ]
A kernel from a measurable space `α` to another measurable space `β` is a measurable function `κ : α → measure β`. The measurable space structure on `measure β` is given by `measure_theory.measure.measurable_space`. A map `κ : α → measure β` is measurable iff `∀ s : set β, measurable_set s → measurable (λ a, κ a s)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_fn_zero : ⇑(0 : kernel α β) = 0
rfl
lemma
probability_theory.kernel.coe_fn_zero
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_fn_add (κ η : kernel α β) : ⇑(κ + η) = κ + η
rfl
lemma
probability_theory.kernel.coe_fn_add
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_add_hom (α β : Type*) [measurable_space α] [measurable_space β] : kernel α β →+ (α → measure β)
⟨coe_fn, coe_fn_zero, coe_fn_add⟩
def
probability_theory.kernel.coe_add_hom
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "measurable_space" ]
Coercion to a function as an additive monoid homomorphism.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
zero_apply (a : α) : (0 : kernel α β) a = 0
rfl
lemma
probability_theory.kernel.zero_apply
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_finset_sum (I : finset ι) (κ : ι → kernel α β) : ⇑(∑ i in I, κ i) = ∑ i in I, κ i
(coe_add_hom α β).map_sum _ _
lemma
probability_theory.kernel.coe_finset_sum
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "finset" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finset_sum_apply (I : finset ι) (κ : ι → kernel α β) (a : α) : (∑ i in I, κ i) a = ∑ i in I, κ i a
by rw [coe_finset_sum, finset.sum_apply]
lemma
probability_theory.kernel.finset_sum_apply
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "finset" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finset_sum_apply' (I : finset ι) (κ : ι → kernel α β) (a : α) (s : set β) : (∑ i in I, κ i) a s = ∑ i in I, κ i a s
by rw [finset_sum_apply, measure.finset_sum_apply]
lemma
probability_theory.kernel.finset_sum_apply'
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "finset" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_markov_kernel (κ : kernel α β) : Prop
(is_probability_measure : ∀ a, is_probability_measure (κ a))
class
probability_theory.is_markov_kernel
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[]
A kernel is a Markov kernel if every measure in its image is a probability measure.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_finite_kernel (κ : kernel α β) : Prop
(exists_univ_le : ∃ C : ℝ≥0∞, C < ∞ ∧ ∀ a, κ a set.univ ≤ C)
class
probability_theory.is_finite_kernel
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[]
A kernel is finite if every measure in its image is finite, with a uniform bound.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_finite_kernel.bound (κ : kernel α β) [h : is_finite_kernel κ] : ℝ≥0∞
h.exists_univ_le.some
def
probability_theory.is_finite_kernel.bound
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[]
A constant `C : ℝ≥0∞` such that `C < ∞` (`is_finite_kernel.bound_lt_top κ`) and for all `a : α` and `s : set β`, `κ a s ≤ C` (`measure_le_bound κ a s`).
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_finite_kernel.bound_lt_top (κ : kernel α β) [h : is_finite_kernel κ] : is_finite_kernel.bound κ < ∞
h.exists_univ_le.some_spec.1
lemma
probability_theory.is_finite_kernel.bound_lt_top
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_finite_kernel.bound_ne_top (κ : kernel α β) [h : is_finite_kernel κ] : is_finite_kernel.bound κ ≠ ∞
(is_finite_kernel.bound_lt_top κ).ne
lemma
probability_theory.is_finite_kernel.bound_ne_top
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
kernel.measure_le_bound (κ : kernel α β) [h : is_finite_kernel κ] (a : α) (s : set β) : κ a s ≤ is_finite_kernel.bound κ
(measure_mono (set.subset_univ s)).trans (h.exists_univ_le.some_spec.2 a)
lemma
probability_theory.kernel.measure_le_bound
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "set.subset_univ" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_finite_kernel_zero (α β : Type*) {mα : measurable_space α} {mβ : measurable_space β} : is_finite_kernel (0 : kernel α β)
⟨⟨0, ennreal.coe_lt_top, λ a, by simp only [kernel.zero_apply, measure.coe_zero, pi.zero_apply, le_zero_iff]⟩⟩
instance
probability_theory.is_finite_kernel_zero
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "ennreal.coe_lt_top", "le_zero_iff", "measurable_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_finite_kernel.add (κ η : kernel α β) [is_finite_kernel κ] [is_finite_kernel η] : is_finite_kernel (κ + η)
begin refine ⟨⟨is_finite_kernel.bound κ + is_finite_kernel.bound η, ennreal.add_lt_top.mpr ⟨is_finite_kernel.bound_lt_top κ, is_finite_kernel.bound_lt_top η⟩, λ a, _⟩⟩, simp_rw [kernel.coe_fn_add, pi.add_apply, measure.coe_add, pi.add_apply], exact add_le_add (kernel.measure_le_bound _ _ _) (kernel.measur...
instance
probability_theory.is_finite_kernel.add
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_markov_kernel.is_probability_measure' [h : is_markov_kernel κ] (a : α) : is_probability_measure (κ a)
is_markov_kernel.is_probability_measure a
instance
probability_theory.is_markov_kernel.is_probability_measure'
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_finite_kernel.is_finite_measure [h : is_finite_kernel κ] (a : α) : is_finite_measure (κ a)
⟨(kernel.measure_le_bound κ a set.univ).trans_lt (is_finite_kernel.bound_lt_top κ)⟩
instance
probability_theory.is_finite_kernel.is_finite_measure
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_markov_kernel.is_finite_kernel [h : is_markov_kernel κ] : is_finite_kernel κ
⟨⟨1, ennreal.one_lt_top, λ a, prob_le_one⟩⟩
instance
probability_theory.is_markov_kernel.is_finite_kernel
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "ennreal.one_lt_top" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ext {η : kernel α β} (h : ∀ a, κ a = η a) : κ = η
by { ext1, ext1 a, exact h a, }
lemma
probability_theory.kernel.ext
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ext_iff {η : kernel α β} : κ = η ↔ ∀ a, κ a = η a
⟨λ h a, by rw h, ext⟩
lemma
probability_theory.kernel.ext_iff
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ext_iff' {η : kernel α β} : κ = η ↔ ∀ a (s : set β) (hs : measurable_set s), κ a s = η a s
by simp_rw [ext_iff, measure.ext_iff]
lemma
probability_theory.kernel.ext_iff'
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "measurable_set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ext_fun {η : kernel α β} (h : ∀ a f, measurable f → ∫⁻ b, f b ∂(κ a) = ∫⁻ b, f b ∂(η a)) : κ = η
begin ext a s hs, specialize h a (s.indicator (λ _, 1)) (measurable.indicator measurable_const hs), simp_rw [lintegral_indicator_const hs, one_mul] at h, rw h, end
lemma
probability_theory.kernel.ext_fun
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "measurable", "measurable.indicator", "measurable_const", "one_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ext_fun_iff {η : kernel α β} : κ = η ↔ ∀ a f, measurable f → ∫⁻ b, f b ∂(κ a) = ∫⁻ b, f b ∂(η a)
⟨λ h a f hf, by rw h, ext_fun⟩
lemma
probability_theory.kernel.ext_fun_iff
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "measurable" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
measurable (κ : kernel α β) : measurable κ
κ.prop
lemma
probability_theory.kernel.measurable
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "measurable" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
measurable_coe (κ : kernel α β) {s : set β} (hs : measurable_set s) : measurable (λ a, κ a s)
(measure.measurable_coe hs).comp (kernel.measurable κ)
lemma
probability_theory.kernel.measurable_coe
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "measurable", "measurable_set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sum [countable ι] (κ : ι → kernel α β) : kernel α β
{ val := λ a, measure.sum (λ n, κ n a), property := begin refine measure.measurable_of_measurable_coe _ (λ s hs, _), simp_rw measure.sum_apply _ hs, exact measurable.ennreal_tsum (λ n, kernel.measurable_coe (κ n) hs), end, }
def
probability_theory.kernel.sum
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "countable", "measurable.ennreal_tsum" ]
Sum of an indexed family of kernels.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sum_apply [countable ι] (κ : ι → kernel α β) (a : α) : kernel.sum κ a = measure.sum (λ n, κ n a)
rfl
lemma
probability_theory.kernel.sum_apply
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "countable" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sum_apply' [countable ι] (κ : ι → kernel α β) (a : α) {s : set β} (hs : measurable_set s) : kernel.sum κ a s = ∑' n, κ n a s
by rw [sum_apply κ a, measure.sum_apply _ hs]
lemma
probability_theory.kernel.sum_apply'
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "countable", "measurable_set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sum_zero [countable ι] : kernel.sum (λ (i : ι), (0 : kernel α β)) = 0
begin ext a s hs : 2, rw [sum_apply' _ a hs], simp only [zero_apply, measure.coe_zero, pi.zero_apply, tsum_zero], end
lemma
probability_theory.kernel.sum_zero
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "countable", "tsum_zero" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sum_comm [countable ι] (κ : ι → ι → kernel α β) : kernel.sum (λ n, kernel.sum (κ n)) = kernel.sum (λ m, kernel.sum (λ n, κ n m))
by { ext a s hs, simp_rw [sum_apply], rw measure.sum_comm, }
lemma
probability_theory.kernel.sum_comm
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "countable" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sum_fintype [fintype ι] (κ : ι → kernel α β) : kernel.sum κ = ∑ i, κ i
by { ext a s hs, simp only [sum_apply' κ a hs, finset_sum_apply' _ κ a s, tsum_fintype], }
lemma
probability_theory.kernel.sum_fintype
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "fintype", "tsum_fintype" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sum_add [countable ι] (κ η : ι → kernel α β) : kernel.sum (λ n, κ n + η n) = kernel.sum κ + kernel.sum η
begin ext a s hs, simp only [coe_fn_add, pi.add_apply, sum_apply, measure.sum_apply _ hs, pi.add_apply, measure.coe_add, tsum_add ennreal.summable ennreal.summable], end
lemma
probability_theory.kernel.sum_add
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "countable", "ennreal.summable", "tsum_add" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
_root_.probability_theory.is_s_finite_kernel (κ : kernel α β) : Prop
(tsum_finite : ∃ κs : ℕ → kernel α β, (∀ n, is_finite_kernel (κs n)) ∧ κ = kernel.sum κs)
class
probability_theory.is_s_finite_kernel
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[]
A kernel is s-finite if it can be written as the sum of countably many finite kernels.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_finite_kernel.is_s_finite_kernel [h : is_finite_kernel κ] : is_s_finite_kernel κ
⟨⟨λ n, if n = 0 then κ else 0, λ n, by { split_ifs, exact h, apply_instance, }, begin ext a s hs, rw kernel.sum_apply' _ _ hs, have : (λ i, ((ite (i = 0) κ 0) a) s) = λ i, ite (i = 0) (κ a s) 0, { ext1 i, split_ifs; refl, }, rw [this, tsum_ite_eq], end⟩⟩
instance
probability_theory.kernel.is_finite_kernel.is_s_finite_kernel
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "tsum_ite_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
seq (κ : kernel α β) [h : is_s_finite_kernel κ] : ℕ → kernel α β
h.tsum_finite.some
def
probability_theory.kernel.seq
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[]
A sequence of finite kernels such that `κ = kernel.sum (seq κ)`. See `is_finite_kernel_seq` and `kernel_sum_seq`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
kernel_sum_seq (κ : kernel α β) [h : is_s_finite_kernel κ] : kernel.sum (seq κ) = κ
h.tsum_finite.some_spec.2.symm
lemma
probability_theory.kernel.kernel_sum_seq
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
measure_sum_seq (κ : kernel α β) [h : is_s_finite_kernel κ] (a : α) : measure.sum (λ n, seq κ n a) = κ a
by rw [← kernel.sum_apply, kernel_sum_seq κ]
lemma
probability_theory.kernel.measure_sum_seq
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_finite_kernel_seq (κ : kernel α β) [h : is_s_finite_kernel κ] (n : ℕ) : is_finite_kernel (kernel.seq κ n)
h.tsum_finite.some_spec.1 n
instance
probability_theory.kernel.is_finite_kernel_seq
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_s_finite_kernel.add (κ η : kernel α β) [is_s_finite_kernel κ] [is_s_finite_kernel η] : is_s_finite_kernel (κ + η)
begin refine ⟨⟨λ n, seq κ n + seq η n, λ n, infer_instance, _⟩⟩, rw [sum_add, kernel_sum_seq κ, kernel_sum_seq η], end
instance
probability_theory.kernel.is_s_finite_kernel.add
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_s_finite_kernel.finset_sum {κs : ι → kernel α β} (I : finset ι) (h : ∀ i ∈ I, is_s_finite_kernel (κs i)) : is_s_finite_kernel (∑ i in I, κs i)
begin classical, unfreezingI { induction I using finset.induction with i I hi_nmem_I h_ind h, { rw [finset.sum_empty], apply_instance, }, { rw finset.sum_insert hi_nmem_I, haveI : is_s_finite_kernel (κs i) := h i (finset.mem_insert_self _ _), haveI : is_s_finite_kernel (∑ (x : ι) in I, κs x), ...
lemma
probability_theory.kernel.is_s_finite_kernel.finset_sum
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "finset", "finset.induction", "finset.mem_insert_of_mem", "finset.mem_insert_self" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_s_finite_kernel_sum_of_denumerable [denumerable ι] {κs : ι → kernel α β} (hκs : ∀ n, is_s_finite_kernel (κs n)) : is_s_finite_kernel (kernel.sum κs)
begin let e : ℕ ≃ (ι × ℕ) := denumerable.equiv₂ ℕ (ι × ℕ), refine ⟨⟨λ n, seq (κs (e n).1) (e n).2, infer_instance, _⟩⟩, have hκ_eq : kernel.sum κs = kernel.sum (λ n, kernel.sum (seq (κs n))), { simp_rw kernel_sum_seq, }, ext a s hs : 2, rw hκ_eq, simp_rw kernel.sum_apply' _ _ hs, change ∑' i m, seq (κs ...
lemma
probability_theory.kernel.is_s_finite_kernel_sum_of_denumerable
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "denumerable", "denumerable.equiv₂", "ennreal.summable", "tsum_prod'" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_s_finite_kernel_sum [countable ι] {κs : ι → kernel α β} (hκs : ∀ n, is_s_finite_kernel (κs n)) : is_s_finite_kernel (kernel.sum κs)
begin casesI fintype_or_infinite ι, { rw sum_fintype, exact is_s_finite_kernel.finset_sum finset.univ (λ i _, hκs i), }, haveI : encodable ι := encodable.of_countable ι, haveI : denumerable ι := denumerable.of_encodable_of_infinite ι, exact is_s_finite_kernel_sum_of_denumerable hκs, end
lemma
probability_theory.kernel.is_s_finite_kernel_sum
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "countable", "denumerable", "denumerable.of_encodable_of_infinite", "encodable", "encodable.of_countable", "finset.univ", "fintype_or_infinite" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
deterministic (f : α → β) (hf : measurable f) : kernel α β
{ val := λ a, measure.dirac (f a), property := begin refine measure.measurable_of_measurable_coe _ (λ s hs, _), simp_rw measure.dirac_apply' _ hs, exact measurable_one.indicator (hf hs), end, }
def
probability_theory.kernel.deterministic
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "measurable" ]
Kernel which to `a` associates the dirac measure at `f a`. This is a Markov kernel.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
deterministic_apply {f : α → β} (hf : measurable f) (a : α) : deterministic f hf a = measure.dirac (f a)
rfl
lemma
probability_theory.kernel.deterministic_apply
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "measurable" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
deterministic_apply' {f : α → β} (hf : measurable f) (a : α) {s : set β} (hs : measurable_set s) : deterministic f hf a s = s.indicator (λ _, 1) (f a)
begin rw [deterministic], change measure.dirac (f a) s = s.indicator 1 (f a), simp_rw measure.dirac_apply' _ hs, end
lemma
probability_theory.kernel.deterministic_apply'
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "measurable", "measurable_set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_markov_kernel_deterministic {f : α → β} (hf : measurable f) : is_markov_kernel (deterministic f hf)
⟨λ a, by { rw deterministic_apply hf, apply_instance, }⟩
instance
probability_theory.kernel.is_markov_kernel_deterministic
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "measurable" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lintegral_deterministic' {f : β → ℝ≥0∞} {g : α → β} {a : α} (hg : measurable g) (hf : measurable f) : ∫⁻ x, f x ∂(kernel.deterministic g hg a) = f (g a)
by rw [kernel.deterministic_apply, lintegral_dirac' _ hf]
lemma
probability_theory.kernel.lintegral_deterministic'
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "measurable" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lintegral_deterministic {f : β → ℝ≥0∞} {g : α → β} {a : α} (hg : measurable g) [measurable_singleton_class β] : ∫⁻ x, f x ∂(kernel.deterministic g hg a) = f (g a)
by rw [kernel.deterministic_apply, lintegral_dirac (g a) f]
lemma
probability_theory.kernel.lintegral_deterministic
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "measurable", "measurable_singleton_class" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
set_lintegral_deterministic' {f : β → ℝ≥0∞} {g : α → β} {a : α} (hg : measurable g) (hf : measurable f) {s : set β} (hs : measurable_set s) [decidable (g a ∈ s)] : ∫⁻ x in s, f x ∂(kernel.deterministic g hg a) = if g a ∈ s then f (g a) else 0
by rw [kernel.deterministic_apply, set_lintegral_dirac' hf hs]
lemma
probability_theory.kernel.set_lintegral_deterministic'
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "measurable", "measurable_set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
set_lintegral_deterministic {f : β → ℝ≥0∞} {g : α → β} {a : α} (hg : measurable g) [measurable_singleton_class β] (s : set β) [decidable (g a ∈ s)] : ∫⁻ x in s, f x ∂(kernel.deterministic g hg a) = if g a ∈ s then f (g a) else 0
by rw [kernel.deterministic_apply, set_lintegral_dirac f s]
lemma
probability_theory.kernel.set_lintegral_deterministic
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "measurable", "measurable_singleton_class" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
integral_deterministic' {E : Type*} [normed_add_comm_group E] [normed_space ℝ E] [complete_space E] {f : β → E} {g : α → β} {a : α} (hg : measurable g) (hf : strongly_measurable f) : ∫ x, f x ∂(kernel.deterministic g hg a) = f (g a)
by rw [kernel.deterministic_apply, integral_dirac' _ _ hf]
lemma
probability_theory.kernel.integral_deterministic'
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "complete_space", "measurable", "normed_add_comm_group", "normed_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
integral_deterministic {E : Type*} [normed_add_comm_group E] [normed_space ℝ E] [complete_space E] {f : β → E} {g : α → β} {a : α} (hg : measurable g) [measurable_singleton_class β] : ∫ x, f x ∂(kernel.deterministic g hg a) = f (g a)
by rw [kernel.deterministic_apply, integral_dirac _ (g a)]
lemma
probability_theory.kernel.integral_deterministic
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "complete_space", "measurable", "measurable_singleton_class", "normed_add_comm_group", "normed_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
set_integral_deterministic' {E : Type*} [normed_add_comm_group E] [normed_space ℝ E] [complete_space E] {f : β → E} {g : α → β} {a : α} (hg : measurable g) (hf : strongly_measurable f) {s : set β} (hs : measurable_set s) [decidable (g a ∈ s)] : ∫ x in s, f x ∂(kernel.deterministic g hg a) = if g a ∈ s then f (g...
by rw [kernel.deterministic_apply, set_integral_dirac' hf _ hs]
lemma
probability_theory.kernel.set_integral_deterministic'
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "complete_space", "measurable", "measurable_set", "normed_add_comm_group", "normed_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
set_integral_deterministic {E : Type*} [normed_add_comm_group E] [normed_space ℝ E] [complete_space E] {f : β → E} {g : α → β} {a : α} (hg : measurable g) [measurable_singleton_class β] (s : set β) [decidable (g a ∈ s)] : ∫ x in s, f x ∂(kernel.deterministic g hg a) = if g a ∈ s then f (g a) else 0
by rw [kernel.deterministic_apply, set_integral_dirac f _ s]
lemma
probability_theory.kernel.set_integral_deterministic
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "complete_space", "measurable", "measurable_singleton_class", "normed_add_comm_group", "normed_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
const (α : Type*) {β : Type*} [measurable_space α] {mβ : measurable_space β} (μβ : measure β) : kernel α β
{ val := λ _, μβ, property := measure.measurable_of_measurable_coe _ (λ s hs, measurable_const), }
def
probability_theory.kernel.const
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "measurable_const", "measurable_space" ]
Constant kernel, which always returns the same measure.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
const_apply (μβ : measure β) (a : α) : const α μβ a = μβ
rfl
lemma
probability_theory.kernel.const_apply
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_finite_kernel_const {μβ : measure β} [hμβ : is_finite_measure μβ] : is_finite_kernel (const α μβ)
⟨⟨μβ set.univ, measure_lt_top _ _, λ a, le_rfl⟩⟩
instance
probability_theory.kernel.is_finite_kernel_const
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_markov_kernel_const {μβ : measure β} [hμβ : is_probability_measure μβ] : is_markov_kernel (const α μβ)
⟨λ a, hμβ⟩
instance
probability_theory.kernel.is_markov_kernel_const
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lintegral_const {f : β → ℝ≥0∞} {μ : measure β} {a : α} : ∫⁻ x, f x ∂(kernel.const α μ a) = ∫⁻ x, f x ∂μ
by rw kernel.const_apply
lemma
probability_theory.kernel.lintegral_const
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
set_lintegral_const {f : β → ℝ≥0∞} {μ : measure β} {a : α} {s : set β} : ∫⁻ x in s, f x ∂(kernel.const α μ a) = ∫⁻ x in s, f x ∂μ
by rw kernel.const_apply
lemma
probability_theory.kernel.set_lintegral_const
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
integral_const {E : Type*} [normed_add_comm_group E] [normed_space ℝ E] [complete_space E] {f : β → E} {μ : measure β} {a : α} : ∫ x, f x ∂(kernel.const α μ a) = ∫ x, f x ∂μ
by rw kernel.const_apply
lemma
probability_theory.kernel.integral_const
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "complete_space", "normed_add_comm_group", "normed_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
set_integral_const {E : Type*} [normed_add_comm_group E] [normed_space ℝ E] [complete_space E] {f : β → E} {μ : measure β} {a : α} {s : set β} : ∫ x in s, f x ∂(kernel.const α μ a) = ∫ x in s, f x ∂μ
by rw kernel.const_apply
lemma
probability_theory.kernel.set_integral_const
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "complete_space", "normed_add_comm_group", "normed_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_fun_of_countable [measurable_space α] {mβ : measurable_space β} [countable α] [measurable_singleton_class α] (f : α → measure β) : kernel α β
{ val := f, property := measurable_of_countable f }
def
probability_theory.kernel.of_fun_of_countable
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "countable", "measurable_of_countable", "measurable_singleton_class", "measurable_space" ]
In a countable space with measurable singletons, every function `α → measure β` defines a kernel.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
restrict (κ : kernel α β) (hs : measurable_set s) : kernel α β
{ val := λ a, (κ a).restrict s, property := begin refine measure.measurable_of_measurable_coe _ (λ t ht, _), simp_rw measure.restrict_apply ht, exact kernel.measurable_coe κ (ht.inter hs), end, }
def
probability_theory.kernel.restrict
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "measurable_set" ]
Kernel given by the restriction of the measures in the image of a kernel to a set.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
restrict_apply (κ : kernel α β) (hs : measurable_set s) (a : α) : kernel.restrict κ hs a = (κ a).restrict s
rfl
lemma
probability_theory.kernel.restrict_apply
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "measurable_set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
restrict_apply' (κ : kernel α β) (hs : measurable_set s) (a : α) (ht : measurable_set t) : kernel.restrict κ hs a t = (κ a) (t ∩ s)
by rw [restrict_apply κ hs a, measure.restrict_apply ht]
lemma
probability_theory.kernel.restrict_apply'
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "measurable_set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
restrict_univ : kernel.restrict κ measurable_set.univ = κ
by { ext1 a, rw [kernel.restrict_apply, measure.restrict_univ], }
lemma
probability_theory.kernel.restrict_univ
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "measurable_set.univ" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lintegral_restrict (κ : kernel α β) (hs : measurable_set s) (a : α) (f : β → ℝ≥0∞) : ∫⁻ b, f b ∂(kernel.restrict κ hs a) = ∫⁻ b in s, f b ∂(κ a)
by rw restrict_apply
lemma
probability_theory.kernel.lintegral_restrict
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "measurable_set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
set_lintegral_restrict (κ : kernel α β) (hs : measurable_set s) (a : α) (f : β → ℝ≥0∞) (t : set β) : ∫⁻ b in t, f b ∂(kernel.restrict κ hs a) = ∫⁻ b in (t ∩ s), f b ∂(κ a)
by rw [restrict_apply, measure.restrict_restrict' hs]
lemma
probability_theory.kernel.set_lintegral_restrict
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "measurable_set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
set_integral_restrict {E : Type*} [normed_add_comm_group E] [normed_space ℝ E] [complete_space E] {f : β → E} {a : α} (hs : measurable_set s) (t : set β) : ∫ x in t, f x ∂(kernel.restrict κ hs a) = ∫ x in (t ∩ s), f x ∂(κ a)
by rw [restrict_apply, measure.restrict_restrict' hs]
lemma
probability_theory.kernel.set_integral_restrict
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "complete_space", "measurable_set", "normed_add_comm_group", "normed_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_finite_kernel.restrict (κ : kernel α β) [is_finite_kernel κ] (hs : measurable_set s) : is_finite_kernel (kernel.restrict κ hs)
begin refine ⟨⟨is_finite_kernel.bound κ, is_finite_kernel.bound_lt_top κ, λ a, _⟩⟩, rw restrict_apply' κ hs a measurable_set.univ, exact measure_le_bound κ a _, end
instance
probability_theory.kernel.is_finite_kernel.restrict
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "measurable_set", "measurable_set.univ" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_s_finite_kernel.restrict (κ : kernel α β) [is_s_finite_kernel κ] (hs : measurable_set s) : is_s_finite_kernel (kernel.restrict κ hs)
begin refine ⟨⟨λ n, kernel.restrict (seq κ n) hs, infer_instance, _⟩⟩, ext1 a, simp_rw [sum_apply, restrict_apply, ← measure.restrict_sum _ hs, ← sum_apply, kernel_sum_seq], end
instance
probability_theory.kernel.is_s_finite_kernel.restrict
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "measurable_set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comap_right (κ : kernel α β) (hf : measurable_embedding f) : kernel α γ
{ val := λ a, (κ a).comap f, property := begin refine measure.measurable_measure.mpr (λ t ht, _), have : (λ a, measure.comap f (κ a) t) = λ a, κ a (f '' t), { ext1 a, rw measure.comap_apply _ hf.injective (λ s' hs', _) _ ht, exact hf.measurable_set_image.mpr hs', }, rw this, exact ke...
def
probability_theory.kernel.comap_right
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "measurable_embedding" ]
Kernel with value `(κ a).comap f`, for a measurable embedding `f`. That is, for a measurable set `t : set β`, `comap_right κ hf a t = κ a (f '' t)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comap_right_apply (κ : kernel α β) (hf : measurable_embedding f) (a : α) : comap_right κ hf a = measure.comap f (κ a)
rfl
lemma
probability_theory.kernel.comap_right_apply
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "measurable_embedding" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comap_right_apply' (κ : kernel α β) (hf : measurable_embedding f) (a : α) {t : set γ} (ht : measurable_set t) : comap_right κ hf a t = κ a (f '' t)
by rw [comap_right_apply, measure.comap_apply _ hf.injective (λ s, hf.measurable_set_image.mpr) _ ht]
lemma
probability_theory.kernel.comap_right_apply'
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "measurable_embedding", "measurable_set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_markov_kernel.comap_right (κ : kernel α β) (hf : measurable_embedding f) (hκ : ∀ a, κ a (set.range f) = 1) : is_markov_kernel (comap_right κ hf)
begin refine ⟨λ a, ⟨_⟩⟩, rw comap_right_apply' κ hf a measurable_set.univ, simp only [set.image_univ, subtype.range_coe_subtype, set.set_of_mem_eq], exact hκ a, end
lemma
probability_theory.kernel.is_markov_kernel.comap_right
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "measurable_embedding", "measurable_set.univ", "set.image_univ", "set.range", "set.set_of_mem_eq", "subtype.range_coe_subtype" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_finite_kernel.comap_right (κ : kernel α β) [is_finite_kernel κ] (hf : measurable_embedding f) : is_finite_kernel (comap_right κ hf)
begin refine ⟨⟨is_finite_kernel.bound κ, is_finite_kernel.bound_lt_top κ, λ a, _⟩⟩, rw comap_right_apply' κ hf a measurable_set.univ, exact measure_le_bound κ a _, end
instance
probability_theory.kernel.is_finite_kernel.comap_right
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "measurable_embedding", "measurable_set.univ" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_s_finite_kernel.comap_right (κ : kernel α β) [is_s_finite_kernel κ] (hf : measurable_embedding f) : is_s_finite_kernel (comap_right κ hf)
begin refine ⟨⟨λ n, comap_right (seq κ n) hf, infer_instance, _⟩⟩, ext1 a, rw sum_apply, simp_rw comap_right_apply _ hf, have : measure.sum (λ n, measure.comap f (seq κ n a)) = measure.comap f (measure.sum (λ n, seq κ n a)), { ext1 t ht, rw [measure.comap_apply _ hf.injective (λ s', hf.measurable_se...
instance
probability_theory.kernel.is_s_finite_kernel.comap_right
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "measurable_embedding" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
piecewise (hs : measurable_set s) (κ η : kernel α β) : kernel α β
{ val := λ a, if a ∈ s then κ a else η a, property := measurable.piecewise hs (kernel.measurable _) (kernel.measurable _) }
def
probability_theory.kernel.piecewise
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "measurable.piecewise", "measurable_set" ]
`piecewise hs κ η` is the kernel equal to `κ` on the measurable set `s` and to `η` on its complement.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
piecewise_apply (a : α) : piecewise hs κ η a = if a ∈ s then κ a else η a
rfl
lemma
probability_theory.kernel.piecewise_apply
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
piecewise_apply' (a : α) (t : set β) : piecewise hs κ η a t = if a ∈ s then κ a t else η a t
by { rw piecewise_apply, split_ifs; refl, }
lemma
probability_theory.kernel.piecewise_apply'
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_markov_kernel.piecewise [is_markov_kernel κ] [is_markov_kernel η] : is_markov_kernel (piecewise hs κ η)
by { refine ⟨λ a, ⟨_⟩⟩, rw [piecewise_apply', measure_univ, measure_univ, if_t_t], }
instance
probability_theory.kernel.is_markov_kernel.piecewise
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_finite_kernel.piecewise [is_finite_kernel κ] [is_finite_kernel η] : is_finite_kernel (piecewise hs κ η)
begin refine ⟨⟨max (is_finite_kernel.bound κ) (is_finite_kernel.bound η), _, λ a, _⟩⟩, { exact max_lt (is_finite_kernel.bound_lt_top κ) (is_finite_kernel.bound_lt_top η), }, rw [piecewise_apply'], exact (ite_le_sup _ _ _).trans (sup_le_sup (measure_le_bound _ _ _) (measure_le_bound _ _ _)), end
instance
probability_theory.kernel.is_finite_kernel.piecewise
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "ite_le_sup", "sup_le_sup" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_s_finite_kernel.piecewise [is_s_finite_kernel κ] [is_s_finite_kernel η] : is_s_finite_kernel (piecewise hs κ η)
begin refine ⟨⟨λ n, piecewise hs (seq κ n) (seq η n), infer_instance, _⟩⟩, ext1 a, simp_rw [sum_apply, kernel.piecewise_apply], split_ifs; exact (measure_sum_seq _ a).symm, end
instance
probability_theory.kernel.is_s_finite_kernel.piecewise
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lintegral_piecewise (a : α) (g : β → ℝ≥0∞) : ∫⁻ b, g b ∂(piecewise hs κ η a) = if a ∈ s then ∫⁻ b, g b ∂(κ a) else ∫⁻ b, g b ∂(η a)
by { simp_rw piecewise_apply, split_ifs; refl, }
lemma
probability_theory.kernel.lintegral_piecewise
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
set_lintegral_piecewise (a : α) (g : β → ℝ≥0∞) (t : set β) : ∫⁻ b in t, g b ∂(piecewise hs κ η a) = if a ∈ s then ∫⁻ b in t, g b ∂(κ a) else ∫⁻ b in t, g b ∂(η a)
by { simp_rw piecewise_apply, split_ifs; refl, }
lemma
probability_theory.kernel.set_lintegral_piecewise
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
integral_piecewise {E : Type*} [normed_add_comm_group E] [normed_space ℝ E] [complete_space E] (a : α) (g : β → E) : ∫ b, g b ∂(piecewise hs κ η a) = if a ∈ s then ∫ b, g b ∂(κ a) else ∫ b, g b ∂(η a)
by { simp_rw piecewise_apply, split_ifs; refl, }
lemma
probability_theory.kernel.integral_piecewise
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "complete_space", "normed_add_comm_group", "normed_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
set_integral_piecewise {E : Type*} [normed_add_comm_group E] [normed_space ℝ E] [complete_space E] (a : α) (g : β → E) (t : set β) : ∫ b in t, g b ∂(piecewise hs κ η a) = if a ∈ s then ∫ b in t, g b ∂(κ a) else ∫ b in t, g b ∂(η a)
by { simp_rw piecewise_apply, split_ifs; refl, }
lemma
probability_theory.kernel.set_integral_piecewise
probability.kernel
src/probability/kernel/basic.lean
[ "measure_theory.integral.bochner", "measure_theory.constructions.prod.basic" ]
[ "complete_space", "normed_add_comm_group", "normed_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comp_prod_fun (κ : kernel α β) (η : kernel (α × β) γ) (a : α) (s : set (β × γ)) : ℝ≥0∞
∫⁻ b, η (a, b) {c | (b, c) ∈ s} ∂(κ a)
def
probability_theory.kernel.comp_prod_fun
probability.kernel
src/probability/kernel/composition.lean
[ "probability.kernel.measurable_integral" ]
[]
Auxiliary function for the definition of the composition-product of two kernels. For all `a : α`, `comp_prod_fun κ η a` is a countably additive function with value zero on the empty set, and the composition-product of kernels is defined in `kernel.comp_prod` through `measure.of_measurable`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comp_prod_fun_empty (κ : kernel α β) (η : kernel (α × β) γ) (a : α) : comp_prod_fun κ η a ∅ = 0
by simp only [comp_prod_fun, set.mem_empty_iff_false, set.set_of_false, measure_empty, measure_theory.lintegral_const, zero_mul]
lemma
probability_theory.kernel.comp_prod_fun_empty
probability.kernel
src/probability/kernel/composition.lean
[ "probability.kernel.measurable_integral" ]
[ "measure_theory.lintegral_const", "set.mem_empty_iff_false", "set.set_of_false", "zero_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comp_prod_fun_Union (κ : kernel α β) (η : kernel (α × β) γ) [is_s_finite_kernel η] (a : α) (f : ℕ → set (β × γ)) (hf_meas : ∀ i, measurable_set (f i)) (hf_disj : pairwise (disjoint on f)) : comp_prod_fun κ η a (⋃ i, f i) = ∑' i, comp_prod_fun κ η a (f i)
begin have h_Union : (λ b, η (a, b) {c : γ | (b, c) ∈ ⋃ i, f i}) = λ b, η (a,b) (⋃ i, {c : γ | (b, c) ∈ f i}), { ext1 b, congr' with c, simp only [set.mem_Union, set.supr_eq_Union, set.mem_set_of_eq], refl, }, rw [comp_prod_fun, h_Union], have h_tsum : (λ b, η (a, b) (⋃ i, {c : γ | (b, c) ∈ f i}...
lemma
probability_theory.kernel.comp_prod_fun_Union
probability.kernel
src/probability/kernel/composition.lean
[ "probability.kernel.measurable_integral" ]
[ "ae_measurable", "disjoint", "measurable_prod_mk_left", "measurable_set", "measurable_snd", "pairwise", "set.bot_eq_empty", "set.le_eq_subset", "set.mem_Union", "set.mem_empty_iff_false", "set.singleton_subset_iff", "set.supr_eq_Union" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comp_prod_fun_tsum_right (κ : kernel α β) (η : kernel (α × β) γ) [is_s_finite_kernel η] (a : α) (hs : measurable_set s) : comp_prod_fun κ η a s = ∑' n, comp_prod_fun κ (seq η n) a s
begin simp_rw [comp_prod_fun, (measure_sum_seq η _).symm], have : ∫⁻ b, measure.sum (λ n, seq η n (a, b)) {c : γ | (b, c) ∈ s} ∂(κ a) = ∫⁻ b, ∑' n, seq η n (a, b) {c : γ | (b, c) ∈ s} ∂(κ a), { congr', ext1 b, rw measure.sum_apply, exact measurable_prod_mk_left hs, }, rw [this, lintegral_tsum (λ...
lemma
probability_theory.kernel.comp_prod_fun_tsum_right
probability.kernel
src/probability/kernel/composition.lean
[ "probability.kernel.measurable_integral" ]
[ "ae_measurable", "measurable_prod_mk_left", "measurable_set", "measurable_snd" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83