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measure_theory.integral.set_to_l1

Extension of a linear function from indicators to L1 #

THIS FILE IS SYNCHRONIZED WITH MATHLIB4. Any changes to this file require a corresponding PR to mathlib4.

Let T : set α → E →L[ℝ] F be additive for measurable sets with finite measure, in the sense that for s, t two such sets, s ∩ t = ∅ → T (s ∪ t) = T s + T t. T is akin to a bilinear map on set α × E, or a linear map on indicator functions.

This file constructs an extension of T to integrable simple functions, which are finite sums of indicators of measurable sets with finite measure, then to integrable functions, which are limits of integrable simple functions.

The main result is a continuous linear map (α →₁[μ] E) →L[ℝ] F. This extension process is used to define the Bochner integral in the measure_theory.integral.bochner file and the conditional expectation of an integrable function in measure_theory.function.conditional_expectation.

Main Definitions #

Properties #

For most properties of set_to_fun, we provide two lemmas. One version uses hypotheses valid on all sets, like T = T', and a second version which uses a primed name uses hypotheses on measurable sets with finite measure, like ∀ s, measurable_set s → μ s < ∞ → T s = T' s.

The lemmas listed here don't show all hypotheses. Refer to the actual lemmas for details.

Linearity:

Other:

If the space is a normed_lattice_add_comm_group and T is such that 0 ≤ T s x for 0 ≤ x, we also prove order-related properties:

Implementation notes #

The starting object T : set α → E →L[ℝ] F matters only through its restriction on measurable sets with finite measure. Its value on other sets is ignored.

def measure_theory.fin_meas_additive {α : Type u_1} {β : Type u_2} [add_monoid β] {m : measurable_space α} (μ : measure_theory.measure α) (T : set α → β) :
Prop

A set function is fin_meas_additive if its value on the union of two disjoint measurable sets with finite measure is the sum of its values on each set.

Equations
theorem measure_theory.fin_meas_additive.smul {α : Type u_1} {𝕜 : Type u_6} {m : measurable_space α} {μ : measure_theory.measure α} {β : Type u_7} [add_comm_monoid β] {T : set α → β} [monoid 𝕜] [distrib_mul_action 𝕜 β] (hT : measure_theory.fin_meas_additive μ T) (c : 𝕜) :
measure_theory.fin_meas_additive μ (λ (s : set α), c • T s)
theorem measure_theory.fin_meas_additive.smul_measure {α : Type u_1} {m : measurable_space α} {μ : measure_theory.measure α} {β : Type u_7} [add_comm_monoid β] {T : set α → β} (c : ennreal) (hc_ne_zero : c ≠ 0) (hT : measure_theory.fin_meas_additive μ T) :
theorem measure_theory.fin_meas_additive.smul_measure_iff {α : Type u_1} {m : measurable_space α} {μ : measure_theory.measure α} {β : Type u_7} [add_comm_monoid β] {T : set α → β} (c : ennreal) (hc_ne_zero : c ≠ 0) (hc_ne_top : c ≠ ⊤) :
theorem measure_theory.fin_meas_additive.map_Union_fin_meas_set_eq_sum {α : Type u_1} {m : measurable_space α} {μ : measure_theory.measure α} {β : Type u_7} [add_comm_monoid β] (T : set α → β) (T_empty : T ∅ = 0) (h_add : measure_theory.fin_meas_additive μ T) {ι : Type u_2} (S : ι → set α) (sι : finset ι) (hS_meas : ∀ (i : ι), measurable_set (S i)) (hSp : ∀ (i : ι), i ∈ sι → ⇑μ (S i) ≠ ⊤) (h_disj : ∀ (i : ι), i ∈ sι → ∀ (j : ι), j ∈ sι → i ≠ j → disjoint (S i) (S j)) :
T (⋃ (i : ι) (H : i ∈ sι), S i) = sι.sum (λ (i : ι), T (S i))
def measure_theory.dominated_fin_meas_additive {α : Type u_1} {β : Type u_2} [seminormed_add_comm_group β] {m : measurable_space α} (μ : measure_theory.measure α) (T : set α → β) (C : ℝ) :
Prop

A fin_meas_additive set function whose norm on every set is less than the measure of the set (up to a multiplicative constant).

Equations
theorem measure_theory.dominated_fin_meas_additive.eq_zero_of_measure_zero {α : Type u_1} {m : measurable_space α} {μ : measure_theory.measure α} {β : Type u_2} [normed_add_comm_group β] {T : set α → β} {C : ℝ} (hT : measure_theory.dominated_fin_meas_additive μ T C) {s : set α} (hs : measurable_set s) (hs_zero : ⇑μ s = 0) :
T s = 0
theorem measure_theory.dominated_fin_meas_additive.eq_zero {α : Type u_1} {β : Type u_2} [normed_add_comm_group β] {T : set α → β} {C : ℝ} {m : measurable_space α} (hT : measure_theory.dominated_fin_meas_additive 0 T C) {s : set α} (hs : measurable_set s) :
T s = 0
theorem measure_theory.dominated_fin_meas_additive.smul {α : Type u_1} {𝕜 : Type u_6} {m : measurable_space α} {μ : measure_theory.measure α} {β : Type u_7} [seminormed_add_comm_group β] {T : set α → β} {C : ℝ} [normed_field 𝕜] [normed_space 𝕜 β] (hT : measure_theory.dominated_fin_meas_additive μ T C) (c : 𝕜) :
noncomputable def measure_theory.simple_func.set_to_simple_func {α : Type u_1} {F : Type u_3} {F' : Type u_4} [normed_add_comm_group F] [normed_space ℝ F] [normed_add_comm_group F'] [normed_space ℝ F'] {m : measurable_space α} (T : set α → (F →L[ℝ] F')) (f : measure_theory.simple_func α F) :
F'

Extend set α → (F →L[ℝ] F') to (α →ₛ F) → F'.

Equations
theorem measure_theory.simple_func.set_to_simple_func_nonneg {α : Type u_1} {G' : Type u_7} {G'' : Type u_8} [normed_lattice_add_comm_group G''] [normed_space ℝ G''] [normed_lattice_add_comm_group G'] [normed_space ℝ G'] {m : measurable_space α} (T : set α → (G' →L[ℝ] G'')) (hT_nonneg : ∀ (s : set α) (x : G'), 0 ≤ x → 0 ≤ ⇑(T s) x) (f : measure_theory.simple_func α G') (hf : 0 ≤ f) :

set_to_L1s does not change if we replace the measure μ by μ' with μ ≪ μ'. The statement uses two functions f and f' because they have to belong to different types, but morally these are the same function (we have f =ᵐ[μ] f').

theorem measure_theory.L1.simple_func.set_to_L1s_smul {α : Type u_1} {F : Type u_3} {𝕜 : Type u_6} [normed_add_comm_group F] [normed_space ℝ F] {m : measurable_space α} {μ : measure_theory.measure α} [normed_field 𝕜] {E : Type u_2} [normed_add_comm_group E] [normed_space ℝ E] [normed_space 𝕜 E] [normed_space 𝕜 F] (T : set α → (E →L[ℝ] F)) (h_zero : ∀ (s : set α), measurable_set s → ⇑μ s = 0 → T s = 0) (h_add : measure_theory.fin_meas_additive μ T) (h_smul : ∀ (c : 𝕜) (s : set α) (x : E), ⇑(T s) (c • x) = c • ⇑(T s) x) (c : 𝕜) (f : ↥(measure_theory.Lp.simple_func E 1 μ)) :
theorem measure_theory.L1.simple_func.set_to_L1s_nonneg {α : Type u_1} {m : measurable_space α} {μ : measure_theory.measure α} {G'' : Type u_7} {G' : Type u_8} [normed_lattice_add_comm_group G'] [normed_space ℝ G'] [normed_lattice_add_comm_group G''] [normed_space ℝ G''] {T : set α → (G'' →L[ℝ] G')} (h_zero : ∀ (s : set α), measurable_set s → ⇑μ s = 0 → T s = 0) (h_add : measure_theory.fin_meas_additive μ T) (hT_nonneg : ∀ (s : set α), measurable_set s → ⇑μ s < ⊤ → ∀ (x : G''), 0 ≤ x → 0 ≤ ⇑(T s) x) {f : ↥(measure_theory.Lp.simple_func G'' 1 μ)} (hf : 0 ≤ f) :
theorem measure_theory.L1.simple_func.set_to_L1s_mono {α : Type u_1} {m : measurable_space α} {μ : measure_theory.measure α} {G'' : Type u_7} {G' : Type u_8} [normed_lattice_add_comm_group G'] [normed_space ℝ G'] [normed_lattice_add_comm_group G''] [normed_space ℝ G''] {T : set α → (G'' →L[ℝ] G')} (h_zero : ∀ (s : set α), measurable_set s → ⇑μ s = 0 → T s = 0) (h_add : measure_theory.fin_meas_additive μ T) (hT_nonneg : ∀ (s : set α), measurable_set s → ⇑μ s < ⊤ → ∀ (x : G''), 0 ≤ x → 0 ≤ ⇑(T s) x) {f g : ↥(measure_theory.Lp.simple_func G'' 1 μ)} (hfg : f ≤ g) :
noncomputable def measure_theory.L1.simple_func.set_to_L1s_clm' (α : Type u_1) (E : Type u_2) {F : Type u_3} (𝕜 : Type u_6) [normed_add_comm_group E] [normed_space ℝ E] [normed_add_comm_group F] [normed_space ℝ F] {m : measurable_space α} (μ : measure_theory.measure α) [normed_field 𝕜] [normed_space 𝕜 E] [normed_space 𝕜 F] {T : set α → (E →L[ℝ] F)} {C : ℝ} (hT : measure_theory.dominated_fin_meas_additive μ T C) (h_smul : ∀ (c : 𝕜) (s : set α) (x : E), ⇑(T s) (c • x) = c • ⇑(T s) x) :

Extend set α → E →L[ℝ] F to (α →₁ₛ[μ] E) →L[𝕜] F.

Equations

Extend set α → E →L[ℝ] F to (α →₁ₛ[μ] E) →L[ℝ] F.

Equations
noncomputable def measure_theory.L1.set_to_L1' {α : Type u_1} {E : Type u_2} {F : Type u_3} (𝕜 : Type u_6) [normed_add_comm_group E] [normed_space ℝ E] [normed_add_comm_group F] [normed_space ℝ F] {m : measurable_space α} {μ : measure_theory.measure α} [nontrivially_normed_field 𝕜] [normed_space 𝕜 E] [normed_space 𝕜 F] [complete_space F] {T : set α → (E →L[ℝ] F)} {C : ℝ} (hT : measure_theory.dominated_fin_meas_additive μ T C) (h_smul : ∀ (c : 𝕜) (s : set α) (x : E), ⇑(T s) (c • x) = c • ⇑(T s) x) :

Extend set α → (E →L[ℝ] F) to (α →₁[μ] E) →L[𝕜] F.

Equations

Extend set α → E →L[ℝ] F to (α →₁[μ] E) →L[ℝ] F.

Equations
theorem measure_theory.L1.set_to_L1_eq_set_to_L1' {α : Type u_1} {E : Type u_2} {F : Type u_3} {𝕜 : Type u_6} [normed_add_comm_group E] [normed_space ℝ E] [normed_add_comm_group F] [normed_space ℝ F] {m : measurable_space α} {μ : measure_theory.measure α} [nontrivially_normed_field 𝕜] [normed_space 𝕜 E] [normed_space 𝕜 F] [complete_space F] {T : set α → (E →L[ℝ] F)} {C : ℝ} (hT : measure_theory.dominated_fin_meas_additive μ T C) (h_smul : ∀ (c : 𝕜) (s : set α) (x : E), ⇑(T s) (c • x) = c • ⇑(T s) x) (f : ↥(measure_theory.Lp E 1 μ)) :
theorem measure_theory.L1.set_to_L1_smul {α : Type u_1} {E : Type u_2} {F : Type u_3} {𝕜 : Type u_6} [normed_add_comm_group E] [normed_space ℝ E] [normed_add_comm_group F] [normed_space ℝ F] {m : measurable_space α} {μ : measure_theory.measure α} [nontrivially_normed_field 𝕜] [normed_space 𝕜 E] [normed_space 𝕜 F] [complete_space F] {T : set α → (E →L[ℝ] F)} {C : ℝ} (hT : measure_theory.dominated_fin_meas_additive μ T C) (h_smul : ∀ (c : 𝕜) (s : set α) (x : E), ⇑(T s) (c • x) = c • ⇑(T s) x) (c : 𝕜) (f : ↥(measure_theory.Lp E 1 μ)) :
theorem measure_theory.L1.set_to_L1_nonneg {α : Type u_1} {m : measurable_space α} {μ : measure_theory.measure α} {G' : Type u_7} {G'' : Type u_8} [normed_lattice_add_comm_group G''] [normed_space ℝ G''] [complete_space G''] [normed_lattice_add_comm_group G'] [normed_space ℝ G'] {T : set α → (G' →L[ℝ] G'')} {C : ℝ} (hT : measure_theory.dominated_fin_meas_additive μ T C) (hT_nonneg : ∀ (s : set α), measurable_set s → ⇑μ s < ⊤ → ∀ (x : G'), 0 ≤ x → 0 ≤ ⇑(T s) x) {f : ↥(measure_theory.Lp G' 1 μ)} (hf : 0 ≤ f) :
theorem measure_theory.L1.set_to_L1_mono {α : Type u_1} {m : measurable_space α} {μ : measure_theory.measure α} {G' : Type u_7} {G'' : Type u_8} [normed_lattice_add_comm_group G''] [normed_space ℝ G''] [complete_space G''] [normed_lattice_add_comm_group G'] [normed_space ℝ G'] {T : set α → (G' →L[ℝ] G'')} {C : ℝ} (hT : measure_theory.dominated_fin_meas_additive μ T C) (hT_nonneg : ∀ (s : set α), measurable_set s → ⇑μ s < ⊤ → ∀ (x : G'), 0 ≤ x → 0 ≤ ⇑(T s) x) {f g : ↥(measure_theory.Lp G' 1 μ)} (hfg : f ≤ g) :
theorem measure_theory.L1.tendsto_set_to_L1 {α : Type u_1} {E : Type u_2} {F : Type u_3} [normed_add_comm_group E] [normed_space ℝ E] [normed_add_comm_group F] [normed_space ℝ F] {m : measurable_space α} {μ : measure_theory.measure α} [complete_space F] {T : set α → (E →L[ℝ] F)} {C : ℝ} (hT : measure_theory.dominated_fin_meas_additive μ T C) (f : ↥(measure_theory.Lp E 1 μ)) {ι : Type u_4} (fs : ι → ↥(measure_theory.Lp E 1 μ)) {l : filter ι} (hfs : filter.tendsto fs l (nhds f)) :

If fs i → f in L1, then set_to_L1 hT (fs i) → set_to_L1 hT f.

noncomputable def measure_theory.set_to_fun {α : Type u_1} {E : Type u_2} {F : Type u_3} [normed_add_comm_group E] [normed_space ℝ E] [normed_add_comm_group F] [normed_space ℝ F] {m : measurable_space α} (μ : measure_theory.measure α) [complete_space F] (T : set α → (E →L[ℝ] F)) {C : ℝ} (hT : measure_theory.dominated_fin_meas_additive μ T C) (f : α → E) :
F

Extend T : set α → E →L[ℝ] F to (α → E) → F (for integrable functions α → E). We set it to 0 if the function is not integrable.

Equations
theorem measure_theory.set_to_fun_add_left' {α : Type u_1} {E : Type u_2} {F : Type u_3} [normed_add_comm_group E] [normed_space ℝ E] [normed_add_comm_group F] [normed_space ℝ F] {m : measurable_space α} {μ : measure_theory.measure α} [complete_space F] {T T' T'' : set α → (E →L[ℝ] F)} {C C' C'' : ℝ} (hT : measure_theory.dominated_fin_meas_additive μ T C) (hT' : measure_theory.dominated_fin_meas_additive μ T' C') (hT'' : measure_theory.dominated_fin_meas_additive μ T'' C'') (h_add : ∀ (s : set α), measurable_set s → ⇑μ s < ⊤ → T'' s = T s + T' s) (f : α → E) :
theorem measure_theory.set_to_fun_smul_left' {α : Type u_1} {E : Type u_2} {F : Type u_3} [normed_add_comm_group E] [normed_space ℝ E] [normed_add_comm_group F] [normed_space ℝ F] {m : measurable_space α} {μ : measure_theory.measure α} [complete_space F] {T T' : set α → (E →L[ℝ] F)} {C C' : ℝ} (hT : measure_theory.dominated_fin_meas_additive μ T C) (hT' : measure_theory.dominated_fin_meas_additive μ T' C') (c : ℝ) (h_smul : ∀ (s : set α), measurable_set s → ⇑μ s < ⊤ → T' s = c • T s) (f : α → E) :
theorem measure_theory.set_to_fun_zero_left' {α : Type u_1} {E : Type u_2} {F : Type u_3} [normed_add_comm_group E] [normed_space ℝ E] [normed_add_comm_group F] [normed_space ℝ F] {m : measurable_space α} {μ : measure_theory.measure α} [complete_space F] {T : set α → (E →L[ℝ] F)} {C : ℝ} {f : α → E} (hT : measure_theory.dominated_fin_meas_additive μ T C) (h_zero : ∀ (s : set α), measurable_set s → ⇑μ s < ⊤ → T s = 0) :
theorem measure_theory.set_to_fun_finset_sum' {α : Type u_1} {E : Type u_2} {F : Type u_3} [normed_add_comm_group E] [normed_space ℝ E] [normed_add_comm_group F] [normed_space ℝ F] {m : measurable_space α} {μ : measure_theory.measure α} [complete_space F] {T : set α → (E →L[ℝ] F)} {C : ℝ} (hT : measure_theory.dominated_fin_meas_additive μ T C) {ι : Type u_4} (s : finset ι) {f : ι → α → E} (hf : ∀ (i : ι), i ∈ s → measure_theory.integrable (f i) μ) :
measure_theory.set_to_fun μ T hT (s.sum (λ (i : ι), f i)) = s.sum (λ (i : ι), measure_theory.set_to_fun μ T hT (f i))
theorem measure_theory.set_to_fun_finset_sum {α : Type u_1} {E : Type u_2} {F : Type u_3} [normed_add_comm_group E] [normed_space ℝ E] [normed_add_comm_group F] [normed_space ℝ F] {m : measurable_space α} {μ : measure_theory.measure α} [complete_space F] {T : set α → (E →L[ℝ] F)} {C : ℝ} (hT : measure_theory.dominated_fin_meas_additive μ T C) {ι : Type u_4} (s : finset ι) {f : ι → α → E} (hf : ∀ (i : ι), i ∈ s → measure_theory.integrable (f i) μ) :
measure_theory.set_to_fun μ T hT (λ (a : α), s.sum (λ (i : ι), f i a)) = s.sum (λ (i : ι), measure_theory.set_to_fun μ T hT (f i))
theorem measure_theory.set_to_fun_smul {α : Type u_1} {E : Type u_2} {F : Type u_3} {𝕜 : Type u_6} [normed_add_comm_group E] [normed_space ℝ E] [normed_add_comm_group F] [normed_space ℝ F] {m : measurable_space α} {μ : measure_theory.measure α} [complete_space F] {T : set α → (E →L[ℝ] F)} {C : ℝ} [nontrivially_normed_field 𝕜] [normed_space 𝕜 E] [normed_space 𝕜 F] (hT : measure_theory.dominated_fin_meas_additive μ T C) (h_smul : ∀ (c : 𝕜) (s : set α) (x : E), ⇑(T s) (c • x) = c • ⇑(T s) x) (c : 𝕜) (f : α → E) :
theorem measure_theory.set_to_fun_indicator_const {α : Type u_1} {E : Type u_2} {F : Type u_3} [normed_add_comm_group E] [normed_space ℝ E] [normed_add_comm_group F] [normed_space ℝ F] {m : measurable_space α} {μ : measure_theory.measure α} [complete_space F] {T : set α → (E →L[ℝ] F)} {C : ℝ} (hT : measure_theory.dominated_fin_meas_additive μ T C) {s : set α} (hs : measurable_set s) (hμs : ⇑μ s ≠ ⊤) (x : E) :
measure_theory.set_to_fun μ T hT (s.indicator (λ (_x : α), x)) = ⇑(T s) x
theorem measure_theory.set_to_fun_mono_left' {α : Type u_1} {E : Type u_2} [normed_add_comm_group E] [normed_space ℝ E] {m : measurable_space α} {μ : measure_theory.measure α} {G'' : Type u_8} [normed_lattice_add_comm_group G''] [normed_space ℝ G''] [complete_space G''] {T T' : set α → (E →L[ℝ] G'')} {C C' : ℝ} (hT : measure_theory.dominated_fin_meas_additive μ T C) (hT' : measure_theory.dominated_fin_meas_additive μ T' C') (hTT' : ∀ (s : set α), measurable_set s → ⇑μ s < ⊤ → ∀ (x : E), ⇑(T s) x ≤ ⇑(T' s) x) (f : α → E) :
theorem measure_theory.set_to_fun_mono_left {α : Type u_1} {E : Type u_2} [normed_add_comm_group E] [normed_space ℝ E] {m : measurable_space α} {μ : measure_theory.measure α} {G'' : Type u_8} [normed_lattice_add_comm_group G''] [normed_space ℝ G''] [complete_space G''] {T T' : set α → (E →L[ℝ] G'')} {C C' : ℝ} (hT : measure_theory.dominated_fin_meas_additive μ T C) (hT' : measure_theory.dominated_fin_meas_additive μ T' C') (hTT' : ∀ (s : set α) (x : E), ⇑(T s) x ≤ ⇑(T' s) x) (f : ↥(measure_theory.Lp E 1 μ)) :
theorem measure_theory.set_to_fun_nonneg {α : Type u_1} {m : measurable_space α} {μ : measure_theory.measure α} {G' : Type u_7} {G'' : Type u_8} [normed_lattice_add_comm_group G''] [normed_space ℝ G''] [complete_space G''] [normed_lattice_add_comm_group G'] [normed_space ℝ G'] {T : set α → (G' →L[ℝ] G'')} {C : ℝ} (hT : measure_theory.dominated_fin_meas_additive μ T C) (hT_nonneg : ∀ (s : set α), measurable_set s → ⇑μ s < ⊤ → ∀ (x : G'), 0 ≤ x → 0 ≤ ⇑(T s) x) {f : α → G'} (hf : 0 ≤ᵐ[μ] f) :
theorem measure_theory.set_to_fun_mono {α : Type u_1} {m : measurable_space α} {μ : measure_theory.measure α} {G' : Type u_7} {G'' : Type u_8} [normed_lattice_add_comm_group G''] [normed_space ℝ G''] [complete_space G''] [normed_lattice_add_comm_group G'] [normed_space ℝ G'] {T : set α → (G' →L[ℝ] G'')} {C : ℝ} (hT : measure_theory.dominated_fin_meas_additive μ T C) (hT_nonneg : ∀ (s : set α), measurable_set s → ⇑μ s < ⊤ → ∀ (x : G'), 0 ≤ x → 0 ≤ ⇑(T s) x) {f g : α → G'} (hf : measure_theory.integrable f μ) (hg : measure_theory.integrable g μ) (hfg : f ≤ᵐ[μ] g) :
theorem measure_theory.tendsto_set_to_fun_of_L1 {α : Type u_1} {E : Type u_2} {F : Type u_3} [normed_add_comm_group E] [normed_space ℝ E] [normed_add_comm_group F] [normed_space ℝ F] {m : measurable_space α} {μ : measure_theory.measure α} [complete_space F] {T : set α → (E →L[ℝ] F)} {C : ℝ} (hT : measure_theory.dominated_fin_meas_additive μ T C) {ι : Type u_4} (f : α → E) (hfi : measure_theory.integrable f μ) {fs : ι → α → E} {l : filter ι} (hfsi : ∀ᶠ (i : ι) in l, measure_theory.integrable (fs i) μ) (hfs : filter.tendsto (λ (i : ι), ∫⁻ (x : α), ↑‖fs i x - f x‖₊ ∂μ) l (nhds 0)) :
filter.tendsto (λ (i : ι), measure_theory.set_to_fun μ T hT (fs i)) l (nhds (measure_theory.set_to_fun μ T hT f))

If F i → f in L1, then set_to_fun μ T hT (F i) → set_to_fun μ T hT f.

theorem measure_theory.continuous_L1_to_L1 {α : Type u_1} {G : Type u_5} [normed_add_comm_group G] {m : measurable_space α} {μ μ' : measure_theory.measure α} (c' : ennreal) (hc' : c' ≠ ⊤) (hμ'_le : μ' ≤ c' • μ) :

Auxiliary lemma for set_to_fun_congr_measure: the function sending f : α →₁[μ] G to f : α →₁[μ'] G is continuous when μ' ≤ c' • μ for c' ≠ ∞.

theorem measure_theory.set_to_fun_congr_measure {α : Type u_1} {E : Type u_2} {F : Type u_3} [normed_add_comm_group E] [normed_space ℝ E] [normed_add_comm_group F] [normed_space ℝ F] {m : measurable_space α} {μ : measure_theory.measure α} [complete_space F] {T : set α → (E →L[ℝ] F)} {C C' : ℝ} {μ' : measure_theory.measure α} (c c' : ennreal) (hc : c ≠ ⊤) (hc' : c' ≠ ⊤) (hμ_le : μ ≤ c • μ') (hμ'_le : μ' ≤ c' • μ) (hT : measure_theory.dominated_fin_meas_additive μ T C) (hT' : measure_theory.dominated_fin_meas_additive μ' T C') (f : α → E) :
theorem measure_theory.tendsto_set_to_fun_of_dominated_convergence {α : Type u_1} {E : Type u_2} {F : Type u_3} [normed_add_comm_group E] [normed_space ℝ E] [normed_add_comm_group F] [normed_space ℝ F] {m : measurable_space α} {μ : measure_theory.measure α} [complete_space F] {T : set α → (E →L[ℝ] F)} {C : ℝ} (hT : measure_theory.dominated_fin_meas_additive μ T C) {fs : ℕ → α → E} {f : α → E} (bound : α → ℝ) (fs_measurable : ∀ (n : ℕ), measure_theory.ae_strongly_measurable (fs n) μ) (bound_integrable : measure_theory.integrable bound μ) (h_bound : ∀ (n : ℕ), ∀ᵐ (a : α) ∂μ, ‖fs n a‖ ≤ bound a) (h_lim : ∀ᵐ (a : α) ∂μ, filter.tendsto (λ (n : ℕ), fs n a) filter.at_top (nhds (f a))) :

Lebesgue dominated convergence theorem provides sufficient conditions under which almost everywhere convergence of a sequence of functions implies the convergence of their image by set_to_fun. We could weaken the condition bound_integrable to require has_finite_integral bound μ instead (i.e. not requiring that bound is measurable), but in all applications proving integrability is easier.

theorem measure_theory.tendsto_set_to_fun_filter_of_dominated_convergence {α : Type u_1} {E : Type u_2} {F : Type u_3} [normed_add_comm_group E] [normed_space ℝ E] [normed_add_comm_group F] [normed_space ℝ F] {m : measurable_space α} {μ : measure_theory.measure α} [complete_space F] {T : set α → (E →L[ℝ] F)} {C : ℝ} (hT : measure_theory.dominated_fin_meas_additive μ T C) {ι : Type u_4} {l : filter ι} [l.is_countably_generated] {fs : ι → α → E} {f : α → E} (bound : α → ℝ) (hfs_meas : ∀ᶠ (n : ι) in l, measure_theory.ae_strongly_measurable (fs n) μ) (h_bound : ∀ᶠ (n : ι) in l, ∀ᵐ (a : α) ∂μ, ‖fs n a‖ ≤ bound a) (bound_integrable : measure_theory.integrable bound μ) (h_lim : ∀ᵐ (a : α) ∂μ, filter.tendsto (λ (n : ι), fs n a) l (nhds (f a))) :
filter.tendsto (λ (n : ι), measure_theory.set_to_fun μ T hT (fs n)) l (nhds (measure_theory.set_to_fun μ T hT f))

Lebesgue dominated convergence theorem for filters with a countable basis

theorem measure_theory.continuous_within_at_set_to_fun_of_dominated {α : Type u_1} {E : Type u_2} {F : Type u_3} [normed_add_comm_group E] [normed_space ℝ E] [normed_add_comm_group F] [normed_space ℝ F] {m : measurable_space α} {μ : measure_theory.measure α} [complete_space F] {T : set α → (E →L[ℝ] F)} {C : ℝ} {X : Type u_7} [topological_space X] [topological_space.first_countable_topology X] (hT : measure_theory.dominated_fin_meas_additive μ T C) {fs : X → α → E} {x₀ : X} {bound : α → ℝ} {s : set X} (hfs_meas : ∀ᶠ (x : X) in nhds_within x₀ s, measure_theory.ae_strongly_measurable (fs x) μ) (h_bound : ∀ᶠ (x : X) in nhds_within x₀ s, ∀ᵐ (a : α) ∂μ, ‖fs x a‖ ≤ bound a) (bound_integrable : measure_theory.integrable bound μ) (h_cont : ∀ᵐ (a : α) ∂μ, continuous_within_at (λ (x : X), fs x a) s x₀) :
continuous_within_at (λ (x : X), measure_theory.set_to_fun μ T hT (fs x)) s x₀
theorem measure_theory.continuous_at_set_to_fun_of_dominated {α : Type u_1} {E : Type u_2} {F : Type u_3} [normed_add_comm_group E] [normed_space ℝ E] [normed_add_comm_group F] [normed_space ℝ F] {m : measurable_space α} {μ : measure_theory.measure α} [complete_space F] {T : set α → (E →L[ℝ] F)} {C : ℝ} {X : Type u_7} [topological_space X] [topological_space.first_countable_topology X] (hT : measure_theory.dominated_fin_meas_additive μ T C) {fs : X → α → E} {x₀ : X} {bound : α → ℝ} (hfs_meas : ∀ᶠ (x : X) in nhds x₀, measure_theory.ae_strongly_measurable (fs x) μ) (h_bound : ∀ᶠ (x : X) in nhds x₀, ∀ᵐ (a : α) ∂μ, ‖fs x a‖ ≤ bound a) (bound_integrable : measure_theory.integrable bound μ) (h_cont : ∀ᵐ (a : α) ∂μ, continuous_at (λ (x : X), fs x a) x₀) :
continuous_at (λ (x : X), measure_theory.set_to_fun μ T hT (fs x)) x₀
theorem measure_theory.continuous_on_set_to_fun_of_dominated {α : Type u_1} {E : Type u_2} {F : Type u_3} [normed_add_comm_group E] [normed_space ℝ E] [normed_add_comm_group F] [normed_space ℝ F] {m : measurable_space α} {μ : measure_theory.measure α} [complete_space F] {T : set α → (E →L[ℝ] F)} {C : ℝ} {X : Type u_7} [topological_space X] [topological_space.first_countable_topology X] (hT : measure_theory.dominated_fin_meas_additive μ T C) {fs : X → α → E} {bound : α → ℝ} {s : set X} (hfs_meas : ∀ (x : X), x ∈ s → measure_theory.ae_strongly_measurable (fs x) μ) (h_bound : ∀ (x : X), x ∈ s → (∀ᵐ (a : α) ∂μ, ‖fs x a‖ ≤ bound a)) (bound_integrable : measure_theory.integrable bound μ) (h_cont : ∀ᵐ (a : α) ∂μ, continuous_on (λ (x : X), fs x a) s) :
continuous_on (λ (x : X), measure_theory.set_to_fun μ T hT (fs x)) s
theorem measure_theory.continuous_set_to_fun_of_dominated {α : Type u_1} {E : Type u_2} {F : Type u_3} [normed_add_comm_group E] [normed_space ℝ E] [normed_add_comm_group F] [normed_space ℝ F] {m : measurable_space α} {μ : measure_theory.measure α} [complete_space F] {T : set α → (E →L[ℝ] F)} {C : ℝ} {X : Type u_7} [topological_space X] [topological_space.first_countable_topology X] (hT : measure_theory.dominated_fin_meas_additive μ T C) {fs : X → α → E} {bound : α → ℝ} (hfs_meas : ∀ (x : X), measure_theory.ae_strongly_measurable (fs x) μ) (h_bound : ∀ (x : X), ∀ᵐ (a : α) ∂μ, ‖fs x a‖ ≤ bound a) (bound_integrable : measure_theory.integrable bound μ) (h_cont : ∀ᵐ (a : α) ∂μ, continuous (λ (x : X), fs x a)) :
continuous (λ (x : X), measure_theory.set_to_fun μ T hT (fs x))