Documentation

Mathlib.MeasureTheory.VectorMeasure.Basic

Basic API for vector measures #

This file develops the basic consequences of countable additivity for vector measures, equips vector measures with their natural algebraic structures, and defines Dirac vector measures.

Main definitions #

@[simp]
theorem MeasureTheory.VectorMeasure.empty {α : Type u_1} {m : MeasurableSpace α} {M : Type u_3} [AddCommMonoid M] [TopologicalSpace M] (v : VectorMeasure α M) :
v = 0
@[simp]
theorem MeasureTheory.VectorMeasure.not_measurable {α : Type u_1} {m : MeasurableSpace α} {M : Type u_3} [AddCommMonoid M] [TopologicalSpace M] (v : VectorMeasure α M) {i : Set α} (hi : ¬MeasurableSet i) :
v i = 0
theorem MeasureTheory.VectorMeasure.m_iUnion {α : Type u_1} {m : MeasurableSpace α} {M : Type u_3} [AddCommMonoid M] [TopologicalSpace M] (v : VectorMeasure α M) {f : Set α} (hf₁ : ∀ (i : ), MeasurableSet (f i)) (hf₂ : Pairwise (Function.onFun Disjoint f)) :
HasSum (fun (i : ) => v (f i)) (v (⋃ (i : ), f i))
@[deprecated DFunLike.coe_injective (since := "2026-06-10")]
theorem MeasureTheory.VectorMeasure.coe_injective {F : Sort u_1} {α : outParam (Sort u_2)} {β : outParam (αSort u_3)} [self : DFunLike F α β] :

Alias of DFunLike.coe_injective.

@[deprecated DFunLike.ext_iff (since := "2026-06-10")]
theorem MeasureTheory.VectorMeasure.ext_iff' {F : Sort u_1} {α : Sort u_2} {β : αSort u_3} [i : DFunLike F α β] {f g : F} :
f = g ∀ (x : α), f x = g x

Alias of DFunLike.ext_iff.

theorem MeasureTheory.VectorMeasure.ext_iff {α : Type u_1} {m : MeasurableSpace α} {M : Type u_3} [AddCommMonoid M] [TopologicalSpace M] (v w : VectorMeasure α M) :
v = w ∀ (i : Set α), MeasurableSet iv i = w i
theorem MeasureTheory.VectorMeasure.ext {α : Type u_1} {m : MeasurableSpace α} {M : Type u_3} [AddCommMonoid M] [TopologicalSpace M] {s t : VectorMeasure α M} (h : ∀ (i : Set α), MeasurableSet is i = t i) :
s = t
theorem MeasureTheory.VectorMeasure.hasSum_of_disjoint_iUnion {α : Type u_1} {β : Type u_2} {m : MeasurableSpace α} {M : Type u_3} [AddCommMonoid M] [TopologicalSpace M] [Countable β] {v : VectorMeasure α M} {f : βSet α} (hm : ∀ (i : β), MeasurableSet (f i)) (hd : Pairwise (Function.onFun Disjoint f)) :
HasSum (fun (i : β) => v (f i)) (v (⋃ (i : β), f i))
theorem MeasureTheory.VectorMeasure.of_if {α : Type u_1} {m : MeasurableSpace α} {M : Type u_3} [AddCommMonoid M] [TopologicalSpace M] {v : VectorMeasure α M} {ι : Type u_4} {x : ι} {B : Set ι} {A : Set α} [Decidable (x B)] :
v (if x B then A else ) = B.indicator (fun (x : ι) => v A) x
theorem MeasureTheory.VectorMeasure.of_disjoint_iUnion {α : Type u_1} {β : Type u_2} {m : MeasurableSpace α} {M : Type u_3} [AddCommMonoid M] [TopologicalSpace M] [Countable β] {v : VectorMeasure α M} {f : βSet α} [T2Space M] (hm : ∀ (i : β), MeasurableSet (f i)) (hd : Pairwise (Function.onFun Disjoint f)) :
v (⋃ (i : β), f i) = ∑' (i : β), v (f i)
theorem MeasureTheory.VectorMeasure.of_biUnion {α : Type u_1} {m : MeasurableSpace α} {M : Type u_3} [AddCommMonoid M] [TopologicalSpace M] {v : VectorMeasure α M} [T2Space M] {ι : Type u_4} {s : Set ι} {f : ιSet α} (hs : s.Countable) (hd : s.Pairwise (Function.onFun Disjoint f)) (h : bs, MeasurableSet (f b)) :
v (⋃ bs, f b) = ∑' (p : s), v (f p)
theorem MeasureTheory.VectorMeasure.of_biUnion_finset {α : Type u_1} {m : MeasurableSpace α} {M : Type u_3} [AddCommMonoid M] [TopologicalSpace M] {v : VectorMeasure α M} [T2Space M] {ι : Type u_4} {s : Finset ι} {f : ιSet α} (hd : (↑s).PairwiseDisjoint f) (hm : bs, MeasurableSet (f b)) :
v (⋃ bs, f b) = ps, v (f p)
theorem MeasureTheory.VectorMeasure.of_union {α : Type u_1} {m : MeasurableSpace α} {M : Type u_3} [AddCommMonoid M] [TopologicalSpace M] {v : VectorMeasure α M} [T2Space M] {A B : Set α} (h : Disjoint A B) (hA : MeasurableSet A) (hB : MeasurableSet B) :
v (A B) = v A + v B
theorem MeasureTheory.VectorMeasure.of_add_of_sdiff {α : Type u_1} {m : MeasurableSpace α} {M : Type u_3} [AddCommMonoid M] [TopologicalSpace M] {v : VectorMeasure α M} [T2Space M] {A B : Set α} (hA : MeasurableSet A) (hB : MeasurableSet B) (h : AB) :
v A + v (B \ A) = v B
@[deprecated MeasureTheory.VectorMeasure.of_add_of_sdiff (since := "2026-06-03")]
theorem MeasureTheory.VectorMeasure.of_add_of_diff {α : Type u_1} {m : MeasurableSpace α} {M : Type u_3} [AddCommMonoid M] [TopologicalSpace M] {v : VectorMeasure α M} [T2Space M] {A B : Set α} (hA : MeasurableSet A) (hB : MeasurableSet B) (h : AB) :
v A + v (B \ A) = v B

Alias of MeasureTheory.VectorMeasure.of_add_of_sdiff.

theorem MeasureTheory.VectorMeasure.of_sdiff {α : Type u_1} {m : MeasurableSpace α} {M : Type u_4} [AddCommGroup M] [TopologicalSpace M] [T2Space M] {v : VectorMeasure α M} {A B : Set α} (hA : MeasurableSet A) (hB : MeasurableSet B) (h : AB) :
v (B \ A) = v B - v A
@[deprecated MeasureTheory.VectorMeasure.of_sdiff (since := "2026-06-03")]
theorem MeasureTheory.VectorMeasure.of_diff {α : Type u_1} {m : MeasurableSpace α} {M : Type u_4} [AddCommGroup M] [TopologicalSpace M] [T2Space M] {v : VectorMeasure α M} {A B : Set α} (hA : MeasurableSet A) (hB : MeasurableSet B) (h : AB) :
v (B \ A) = v B - v A

Alias of MeasureTheory.VectorMeasure.of_sdiff.

theorem MeasureTheory.VectorMeasure.of_compl {α : Type u_1} {m : MeasurableSpace α} {M : Type u_4} [AddCommGroup M] [TopologicalSpace M] [T2Space M] {v : VectorMeasure α M} {A : Set α} (hA : MeasurableSet A) :
v A = v Set.univ - v A
theorem MeasureTheory.VectorMeasure.of_sdiff_of_sdiff_eq_zero {α : Type u_1} {m : MeasurableSpace α} {M : Type u_3} [AddCommMonoid M] [TopologicalSpace M] {v : VectorMeasure α M} [T2Space M] {A B : Set α} (hA : MeasurableSet A) (hB : MeasurableSet B) (h' : v (B \ A) = 0) :
v (A \ B) + v B = v A
@[deprecated MeasureTheory.VectorMeasure.of_sdiff_of_sdiff_eq_zero (since := "2026-06-03")]
theorem MeasureTheory.VectorMeasure.of_diff_of_diff_eq_zero {α : Type u_1} {m : MeasurableSpace α} {M : Type u_3} [AddCommMonoid M] [TopologicalSpace M] {v : VectorMeasure α M} [T2Space M] {A B : Set α} (hA : MeasurableSet A) (hB : MeasurableSet B) (h' : v (B \ A) = 0) :
v (A \ B) + v B = v A

Alias of MeasureTheory.VectorMeasure.of_sdiff_of_sdiff_eq_zero.

theorem MeasureTheory.VectorMeasure.of_iUnion_nonneg {α : Type u_1} {β : Type u_2} {m : MeasurableSpace α} [Countable β] {f : βSet α} {M : Type u_4} [TopologicalSpace M] [AddCommMonoid M] [PartialOrder M] [IsOrderedAddMonoid M] [OrderClosedTopology M] {v : VectorMeasure α M} (hf₁ : ∀ (i : β), MeasurableSet (f i)) (hf₂ : Pairwise (Function.onFun Disjoint f)) (hf₃ : ∀ (i : β), 0 v (f i)) :
0 v (⋃ (i : β), f i)
theorem MeasureTheory.VectorMeasure.of_iUnion_nonpos {α : Type u_1} {β : Type u_2} {m : MeasurableSpace α} [Countable β] {f : βSet α} {M : Type u_4} [TopologicalSpace M] [AddCommMonoid M] [PartialOrder M] [IsOrderedAddMonoid M] [OrderClosedTopology M] {v : VectorMeasure α M} (hf₁ : ∀ (i : β), MeasurableSet (f i)) (hf₂ : Pairwise (Function.onFun Disjoint f)) (hf₃ : ∀ (i : β), v (f i) 0) :
v (⋃ (i : β), f i) 0
theorem MeasureTheory.VectorMeasure.of_nonneg_disjoint_union_eq_zero {α : Type u_1} {m : MeasurableSpace α} {s : SignedMeasure α} {A B : Set α} (h : Disjoint A B) (hA₁ : MeasurableSet A) (hB₁ : MeasurableSet B) (hA₂ : 0 s A) (hB₂ : 0 s B) (hAB : s (A B) = 0) :
s A = 0
theorem MeasureTheory.VectorMeasure.of_nonpos_disjoint_union_eq_zero {α : Type u_1} {m : MeasurableSpace α} {s : SignedMeasure α} {A B : Set α} (h : Disjoint A B) (hA₁ : MeasurableSet A) (hB₁ : MeasurableSet B) (hA₂ : s A 0) (hB₂ : s B 0) (hAB : s (A B) = 0) :
s A = 0
theorem MeasureTheory.VectorMeasure.tendsto_vectorMeasure_iUnion_atTop_nat {α : Type u_1} {m : MeasurableSpace α} {M : Type u_3} [AddCommMonoid M] [TopologicalSpace M] {v : VectorMeasure α M} [T2Space M] {s : Set α} (hm : Monotone s) (hs : ∀ (i : ), MeasurableSet (s i)) :
Filter.Tendsto (fun (n : ) => v (s n)) Filter.atTop (nhds (v (⋃ (n : ), s n)))
theorem MeasureTheory.VectorMeasure.tendsto_vectorMeasure_iInter_atTop_nat {α : Type u_1} {m : MeasurableSpace α} {M : Type u_4} [AddCommGroup M] [TopologicalSpace M] [T2Space M] [ContinuousSub M] {v : VectorMeasure α M} {s : Set α} (hm : Antitone s) (hs : ∀ (i : ), MeasurableSet (s i)) :
Filter.Tendsto (fun (n : ) => v (s n)) Filter.atTop (nhds (v (⋂ (n : ), s n)))
theorem MeasureTheory.VectorMeasure.ext_of_generateFrom {M : Type u_4} [AddCommGroup M] [TopologicalSpace M] [T2Space M] {X : Type u_5} {mX : MeasurableSpace X} {μ ν : VectorMeasure X M} (C : Set (Set X)) (hμν : sC, μ s = ν s) (hA : mX = MeasurableSpace.generateFrom C) (hC : IsPiSystem C) (h_univ : μ Set.univ = ν Set.univ) :
μ = ν

If two vector measures give the same mass to the whole space and coincide on a generating π-system, then they coincide.

@[instance_reducible]

Given a scalar r and a vector measure v, smul r v is the vector measure corresponding to the set function s : Set α => r • (v s).

Equations
Instances For
    @[deprecated FunLike.coe_smul (since := "2026-06-10")]
    theorem MeasureTheory.VectorMeasure.coe_smul {M : Type u_1} {F : Type u_2} {α : Type u_4} {β : Type u_5} [FunLike F α β] [SMul M F] [SMul M β] [IsSMulApply M F α β] (n : M) (f : F) :
    ⇑(n f) = n f

    Alias of FunLike.coe_smul.

    @[deprecated smul_apply (since := "2026-06-10")]
    theorem MeasureTheory.VectorMeasure.smul_apply {M : Type u_1} {F : Type u_2} {α : outParam (Type u_3)} {β : outParam (Type u_4)} {inst✝ : FunLike F α β} {inst✝¹ : SMul M β} {inst✝² : SMul M F} [self : IsSMulApply M F α β] (f : F) (r : M) (x : α) :
    (r f) x = r f x

    Alias of smul_apply.

    @[instance_reducible]
    Equations
    @[deprecated FunLike.coe_zero (since := "2026-06-10")]
    theorem MeasureTheory.VectorMeasure.coe_zero {F : Type u_2} {α : Type u_4} {β : Type u_5} [FunLike F α β] [Zero F] [Zero β] [IsZeroApply F α β] :
    0 = 0

    Alias of FunLike.coe_zero.

    @[deprecated zero_apply (since := "2026-06-10")]
    theorem MeasureTheory.VectorMeasure.zero_apply {F : Type u_1} {α : outParam (Type u_2)} {β : outParam (Type u_3)} {inst✝ : FunLike F α β} {inst✝¹ : Zero β} {inst✝² : Zero F} [self : IsZeroApply F α β] (x : α) :
    0 x = 0

    Alias of zero_apply.

    The sum of two vector measure is a vector measure.

    Equations
    • v.add w = { measureOf' := v + w, empty' := , not_measurable' := , m_iUnion' := }
    Instances For
      @[deprecated FunLike.coe_add (since := "2026-06-10")]
      theorem MeasureTheory.VectorMeasure.coe_add {F : Type u_2} {α : Type u_4} {β : Type u_5} [FunLike F α β] [Add F] [Add β] [IsAddApply F α β] (f g : F) :
      ⇑(f + g) = f + g

      Alias of FunLike.coe_add.

      @[deprecated add_apply (since := "2026-06-10")]
      theorem MeasureTheory.VectorMeasure.add_apply {F : Type u_1} {α : outParam (Type u_2)} {β : outParam (Type u_3)} {inst✝ : FunLike F α β} {inst✝¹ : Add β} {inst✝² : Add F} [self : IsAddApply F α β] (f g : F) (x : α) :
      (f + g) x = f x + g x

      Alias of add_apply.

      @[instance_reducible]
      Equations
      • One or more equations did not get rendered due to their size.
      @[deprecated FunLike.coeAddMonoidHom (since := "2026-06-10")]
      def MeasureTheory.VectorMeasure.coeFnAddMonoidHom (F : Type u_1) (α : Type u_2) (β : Type u_3) [FunLike F α β] [AddZero F] [AddZeroClass β] [IsZeroApply F α β] [IsAddApply F α β] :
      F →+ αβ

      Alias of FunLike.coeAddMonoidHom.

      Equations
      Instances For
        @[deprecated FunLike.coeAddMonoidHom_apply (since := "2026-06-10")]
        theorem MeasureTheory.VectorMeasure.coeFnAddMonoidHom_apply {F : Type u_1} {α : Type u_2} {β : Type u_3} [FunLike F α β] [AddZero F] [AddZeroClass β] [IsZeroApply F α β] [IsAddApply F α β] (f : F) :
        (FunLike.coeAddMonoidHom F α β) f = f

        Alias of FunLike.coeAddMonoidHom_apply.

        @[deprecated FunLike.coe_sum (since := "2026-06-10")]
        theorem MeasureTheory.VectorMeasure.coe_finsetSum {F : Type u_8} {α : Type u_9} {β : Type u_10} {ι : Type u_11} [FunLike F α β] [AddCommMonoid β] [AddCommMonoid F] [IsZeroApply F α β] [IsAddApply F α β] (s : Finset ι) (f : ιF) :
        (∑ is, f i) = is, (f i)

        Alias of FunLike.coe_sum.

        The negative of a vector measure is a vector measure.

        Equations
        • v.neg = { measureOf' := -v, empty' := , not_measurable' := , m_iUnion' := }
        Instances For
          @[deprecated FunLike.coe_neg (since := "2026-06-10")]
          theorem MeasureTheory.VectorMeasure.coe_neg {F : Type u_2} {α : Type u_4} {β : Type u_5} [FunLike F α β] [Neg F] [Neg β] [IsNegApply F α β] (f : F) :
          ⇑(-f) = -f

          Alias of FunLike.coe_neg.

          @[deprecated neg_apply (since := "2026-06-10")]
          theorem MeasureTheory.VectorMeasure.neg_apply {F : Type u_1} {α : outParam (Type u_2)} {β : outParam (Type u_3)} {inst✝ : FunLike F α β} {inst✝¹ : Neg β} {inst✝² : Neg F} [self : IsNegApply F α β] (f : F) (x : α) :
          (-f) x = -f x

          Alias of neg_apply.

          The difference of two vector measure is a vector measure.

          Equations
          • v.sub w = { measureOf' := v - w, empty' := , not_measurable' := , m_iUnion' := }
          Instances For
            @[deprecated FunLike.coe_sub (since := "2026-06-10")]
            theorem MeasureTheory.VectorMeasure.coe_sub {F : Type u_2} {α : Type u_4} {β : Type u_5} [FunLike F α β] [Sub F] [Sub β] [IsSubApply F α β] (f g : F) :
            ⇑(f - g) = f - g

            Alias of FunLike.coe_sub.

            @[deprecated sub_apply (since := "2026-06-10")]
            theorem MeasureTheory.VectorMeasure.sub_apply {F : Type u_1} {α : outParam (Type u_2)} {β : outParam (Type u_3)} {inst✝ : FunLike F α β} {inst✝¹ : Sub β} {inst✝² : Sub F} [self : IsSubApply F α β] (f g : F) (x : α) :
            (f - g) x = f x - g x

            Alias of sub_apply.

            @[instance_reducible]
            Equations
            • One or more equations did not get rendered due to their size.
            @[instance_reducible]
            Equations
            @[instance_reducible]
            Equations
            noncomputable def MeasureTheory.VectorMeasure.dirac {β : Type u_2} {M : Type u_3} [AddCommMonoid M] [TopologicalSpace M] [MeasurableSpace β] (x : β) (v : M) :

            The Dirac vector measure with mass v at a point x. It gives mass v to measurable sets containing x, and 0 otherwise.

            Equations
            Instances For
              @[simp]
              theorem MeasureTheory.VectorMeasure.dirac_apply_of_mem {β : Type u_2} {M : Type u_3} [AddCommMonoid M] [TopologicalSpace M] [MeasurableSpace β] {x : β} {v : M} {s : Set β} (hs : MeasurableSet s) (hx : x s) :
              (dirac x v) s = v
              @[simp]
              theorem MeasureTheory.VectorMeasure.dirac_apply_of_notMem {β : Type u_2} {M : Type u_3} [AddCommMonoid M] [TopologicalSpace M] [MeasurableSpace β] {x : β} {v : M} {s : Set β} (hx : xs) :
              (dirac x v) s = 0
              @[simp]
              theorem MeasureTheory.VectorMeasure.dirac_zero {β : Type u_2} {M : Type u_3} [AddCommMonoid M] [TopologicalSpace M] [MeasurableSpace β] {x : β} :
              dirac x 0 = 0