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Mathlib.MeasureTheory.Function.Holder

Continuous bilinear maps on MeasureTheory.Lp spaces #

Given a continuous bilinear map B : E →L[𝕜] F →L[𝕜] G, we define an associated map ContinuousLinearMap.holder : Lp E p μ → Lp F q μ → Lp G r μ where p q r are a Hölder triple. We bundle this into a bilinear map ContinuousLinearMap.holderₗ and a continuous bilinear map ContinuousLinearMap.holderL under some additional assumptions.

We also declare a heterogeneous scalar multiplication (HSMul) instance on MeasureTheory.Lp spaces. Although this could use the ContinuousLinearMap.holder construction above, we opt not to do so in order to minimize the necessary type class assumptions.

When p q : ℝ≥0∞ are Hölder conjugate (i.e., HolderConjugate p q), we also construct the natural map ContinuousLinearMap.lpPairing : Lp E p μ →L[𝕜] Lp F q μ →L[𝕜] G given by fun f g ↦ ∫ x, B (f x) (g x) ∂μ. When B := (NormedSpace.inclusionInDoubleDual 𝕜 E).flip, this is the natural map Lp (Dual 𝕜 E) p μ →L[𝕜] Dual 𝕜 (Lp E q μ).

Induced bilinear maps #

def ContinuousLinearMap.holder {α : Type u_1} {𝕜 : Type u_2} {E : Type u_3} {F : Type u_4} {G : Type u_5} {m : MeasurableSpace α} {μ : MeasureTheory.Measure α} {p q : ENNReal} (r : ENNReal) [hpqr : p.HolderTriple q r] [NontriviallyNormedField 𝕜] [NormedAddCommGroup E] [NormedAddCommGroup F] [NormedAddCommGroup G] [NormedSpace 𝕜 E] [NormedSpace 𝕜 F] [NormedSpace 𝕜 G] (B : E →L[𝕜] F →L[𝕜] G) (f : (MeasureTheory.Lp E p μ)) (g : (MeasureTheory.Lp F q μ)) :
(MeasureTheory.Lp G r μ)

The map between MeasuryTheory.Lp spaces satisfying ENNReal.HolderTriple induced by a continuous bilinear map on the underlying spaces.

Equations
Instances For
    theorem ContinuousLinearMap.coeFn_holder {α : Type u_1} {𝕜 : Type u_2} {E : Type u_3} {F : Type u_4} {G : Type u_5} {m : MeasurableSpace α} {μ : MeasureTheory.Measure α} {p q r : ENNReal} [hpqr : p.HolderTriple q r] [NontriviallyNormedField 𝕜] [NormedAddCommGroup E] [NormedAddCommGroup F] [NormedAddCommGroup G] [NormedSpace 𝕜 E] [NormedSpace 𝕜 F] [NormedSpace 𝕜 G] (B : E →L[𝕜] F →L[𝕜] G) (f : (MeasureTheory.Lp E p μ)) (g : (MeasureTheory.Lp F q μ)) :
    (holder r B f g) =ᵐ[μ] fun (x : α) => (B (f x)) (g x)
    theorem ContinuousLinearMap.nnnorm_holder_apply_apply_le {α : Type u_1} {𝕜 : Type u_2} {E : Type u_3} {F : Type u_4} {G : Type u_5} {m : MeasurableSpace α} {μ : MeasureTheory.Measure α} {p q r : ENNReal} [hpqr : p.HolderTriple q r] [NontriviallyNormedField 𝕜] [NormedAddCommGroup E] [NormedAddCommGroup F] [NormedAddCommGroup G] [NormedSpace 𝕜 E] [NormedSpace 𝕜 F] [NormedSpace 𝕜 G] (B : E →L[𝕜] F →L[𝕜] G) (f : (MeasureTheory.Lp E p μ)) (g : (MeasureTheory.Lp F q μ)) :
    theorem ContinuousLinearMap.norm_holder_apply_apply_le {α : Type u_1} {𝕜 : Type u_2} {E : Type u_3} {F : Type u_4} {G : Type u_5} {m : MeasurableSpace α} {μ : MeasureTheory.Measure α} {p q r : ENNReal} [hpqr : p.HolderTriple q r] [NontriviallyNormedField 𝕜] [NormedAddCommGroup E] [NormedAddCommGroup F] [NormedAddCommGroup G] [NormedSpace 𝕜 E] [NormedSpace 𝕜 F] [NormedSpace 𝕜 G] (B : E →L[𝕜] F →L[𝕜] G) (f : (MeasureTheory.Lp E p μ)) (g : (MeasureTheory.Lp F q μ)) :
    theorem ContinuousLinearMap.holder_add_left {α : Type u_1} {𝕜 : Type u_2} {E : Type u_3} {F : Type u_4} {G : Type u_5} {m : MeasurableSpace α} {μ : MeasureTheory.Measure α} {p q r : ENNReal} [hpqr : p.HolderTriple q r] [NontriviallyNormedField 𝕜] [NormedAddCommGroup E] [NormedAddCommGroup F] [NormedAddCommGroup G] [NormedSpace 𝕜 E] [NormedSpace 𝕜 F] [NormedSpace 𝕜 G] (B : E →L[𝕜] F →L[𝕜] G) (f₁ f₂ : (MeasureTheory.Lp E p μ)) (g : (MeasureTheory.Lp F q μ)) :
    holder r B (f₁ + f₂) g = holder r B f₁ g + holder r B f₂ g
    theorem ContinuousLinearMap.holder_add_right {α : Type u_1} {𝕜 : Type u_2} {E : Type u_3} {F : Type u_4} {G : Type u_5} {m : MeasurableSpace α} {μ : MeasureTheory.Measure α} {p q r : ENNReal} [hpqr : p.HolderTriple q r] [NontriviallyNormedField 𝕜] [NormedAddCommGroup E] [NormedAddCommGroup F] [NormedAddCommGroup G] [NormedSpace 𝕜 E] [NormedSpace 𝕜 F] [NormedSpace 𝕜 G] (B : E →L[𝕜] F →L[𝕜] G) (f : (MeasureTheory.Lp E p μ)) (g₁ g₂ : (MeasureTheory.Lp F q μ)) :
    holder r B f (g₁ + g₂) = holder r B f g₁ + holder r B f g₂
    theorem ContinuousLinearMap.holder_smul_left {α : Type u_1} {𝕜 : Type u_2} {E : Type u_3} {F : Type u_4} {G : Type u_5} {m : MeasurableSpace α} {μ : MeasureTheory.Measure α} {p q r : ENNReal} [hpqr : p.HolderTriple q r] [NontriviallyNormedField 𝕜] [NormedAddCommGroup E] [NormedAddCommGroup F] [NormedAddCommGroup G] [NormedSpace 𝕜 E] [NormedSpace 𝕜 F] [NormedSpace 𝕜 G] (B : E →L[𝕜] F →L[𝕜] G) (c : 𝕜) (f : (MeasureTheory.Lp E p μ)) (g : (MeasureTheory.Lp F q μ)) :
    holder r B (c f) g = c holder r B f g
    theorem ContinuousLinearMap.holder_smul_right {α : Type u_1} {𝕜 : Type u_2} {E : Type u_3} {F : Type u_4} {G : Type u_5} {m : MeasurableSpace α} {μ : MeasureTheory.Measure α} {p q r : ENNReal} [hpqr : p.HolderTriple q r] [NontriviallyNormedField 𝕜] [NormedAddCommGroup E] [NormedAddCommGroup F] [NormedAddCommGroup G] [NormedSpace 𝕜 E] [NormedSpace 𝕜 F] [NormedSpace 𝕜 G] (B : E →L[𝕜] F →L[𝕜] G) (c : 𝕜) (f : (MeasureTheory.Lp E p μ)) (g : (MeasureTheory.Lp F q μ)) :
    holder r B f (c g) = c holder r B f g
    def ContinuousLinearMap.holderₗ {α : Type u_1} {𝕜 : Type u_2} {E : Type u_3} {F : Type u_4} {G : Type u_5} {m : MeasurableSpace α} (μ : MeasureTheory.Measure α) (p q r : ENNReal) [hpqr : p.HolderTriple q r] [NontriviallyNormedField 𝕜] [NormedAddCommGroup E] [NormedAddCommGroup F] [NormedAddCommGroup G] [NormedSpace 𝕜 E] [NormedSpace 𝕜 F] [NormedSpace 𝕜 G] (B : E →L[𝕜] F →L[𝕜] G) :
    (MeasureTheory.Lp E p μ) →ₗ[𝕜] (MeasureTheory.Lp F q μ) →ₗ[𝕜] (MeasureTheory.Lp G r μ)

    MeasureTheory.Lp.holder as a bilinear map.

    Equations
    Instances For
      @[simp]
      theorem ContinuousLinearMap.holderₗ_apply_apply {α : Type u_1} {𝕜 : Type u_2} {E : Type u_3} {F : Type u_4} {G : Type u_5} {m : MeasurableSpace α} (μ : MeasureTheory.Measure α) (p q r : ENNReal) [hpqr : p.HolderTriple q r] [NontriviallyNormedField 𝕜] [NormedAddCommGroup E] [NormedAddCommGroup F] [NormedAddCommGroup G] [NormedSpace 𝕜 E] [NormedSpace 𝕜 F] [NormedSpace 𝕜 G] (B : E →L[𝕜] F →L[𝕜] G) (m✝ : (MeasureTheory.Lp E p μ)) (g : (MeasureTheory.Lp F q μ)) :
      ((holderₗ μ p q r B) m✝) g = holder r B m✝ g
      def ContinuousLinearMap.holderL {α : Type u_1} {𝕜 : Type u_2} {E : Type u_3} {F : Type u_4} {G : Type u_5} {m : MeasurableSpace α} (μ : MeasureTheory.Measure α) (p q r : ENNReal) [hpqr : p.HolderTriple q r] [NontriviallyNormedField 𝕜] [NormedAddCommGroup E] [NormedAddCommGroup F] [NormedAddCommGroup G] [NormedSpace 𝕜 E] [NormedSpace 𝕜 F] [NormedSpace 𝕜 G] (B : E →L[𝕜] F →L[𝕜] G) [Fact (1 p)] [Fact (1 q)] [Fact (1 r)] :
      (MeasureTheory.Lp E p μ) →L[𝕜] (MeasureTheory.Lp F q μ) →L[𝕜] (MeasureTheory.Lp G r μ)

      MeasureTheory.Lp.holder as a continuous bilinear map.

      Equations
      Instances For
        @[simp]
        theorem ContinuousLinearMap.holderL_apply_apply {α : Type u_1} {𝕜 : Type u_2} {E : Type u_3} {F : Type u_4} {G : Type u_5} {m : MeasurableSpace α} (μ : MeasureTheory.Measure α) (p q r : ENNReal) [hpqr : p.HolderTriple q r] [NontriviallyNormedField 𝕜] [NormedAddCommGroup E] [NormedAddCommGroup F] [NormedAddCommGroup G] [NormedSpace 𝕜 E] [NormedSpace 𝕜 F] [NormedSpace 𝕜 G] (B : E →L[𝕜] F →L[𝕜] G) [Fact (1 p)] [Fact (1 q)] [Fact (1 r)] (x : (MeasureTheory.Lp E p μ)) (g : (MeasureTheory.Lp F q μ)) :
        ((holderL μ p q r B) x) g = holder r B x g
        theorem ContinuousLinearMap.norm_holderL_le {α : Type u_1} {𝕜 : Type u_2} {E : Type u_3} {F : Type u_4} {G : Type u_5} {m : MeasurableSpace α} {μ : MeasureTheory.Measure α} {p q r : ENNReal} [hpqr : p.HolderTriple q r] [NontriviallyNormedField 𝕜] [NormedAddCommGroup E] [NormedAddCommGroup F] [NormedAddCommGroup G] [NormedSpace 𝕜 E] [NormedSpace 𝕜 F] [NormedSpace 𝕜 G] (B : E →L[𝕜] F →L[𝕜] G) [Fact (1 p)] [Fact (1 q)] [Fact (1 r)] :
        def ContinuousLinearMap.lpPairing {α : Type u_1} {𝕜 : Type u_2} {E : Type u_3} {F : Type u_4} {G : Type u_5} {m : MeasurableSpace α} (μ : MeasureTheory.Measure α) (p q : ENNReal) [NontriviallyNormedField 𝕜] [NormedAddCommGroup E] [NormedAddCommGroup F] [NormedAddCommGroup G] [NormedSpace 𝕜 E] [NormedSpace 𝕜 F] [NormedSpace 𝕜 G] [Fact (1 p)] [Fact (1 q)] [p.HolderConjugate q] [NormedSpace G] [SMulCommClass 𝕜 G] [CompleteSpace G] (B : E →L[𝕜] F →L[𝕜] G) :
        (MeasureTheory.Lp E p μ) →L[𝕜] (MeasureTheory.Lp F q μ) →L[𝕜] G

        The natural pairing between Lp E p μ and Lp F q μ (for Hölder conjugate p q : ℝ≥0∞) with values in a space G induced by a bilinear map B : E →L[𝕜] F →L[𝕜] G.

        This is given by ∫ x, B (f x) (g x) ∂μ.

        In the special case when B := (NormedSpace.inclusionInDoubleDual 𝕜 E).flip, which is definitionally the same as B := ContinuousLinearMap.id 𝕜 (E →L[𝕜] 𝕜), this is the natural map Lp (Dual 𝕜 E) p μ →L[𝕜] Dual 𝕜 (Lp E q μ).

        Equations
        Instances For
          theorem ContinuousLinearMap.lpPairing_eq_integral {α : Type u_1} {𝕜 : Type u_2} {E : Type u_3} {F : Type u_4} {G : Type u_5} {m : MeasurableSpace α} {μ : MeasureTheory.Measure α} {p q : ENNReal} [NontriviallyNormedField 𝕜] [NormedAddCommGroup E] [NormedAddCommGroup F] [NormedAddCommGroup G] [NormedSpace 𝕜 E] [NormedSpace 𝕜 F] [NormedSpace 𝕜 G] (B : E →L[𝕜] F →L[𝕜] G) [Fact (1 p)] [Fact (1 q)] [p.HolderConjugate q] [NormedSpace G] [SMulCommClass 𝕜 G] [CompleteSpace G] (f : (MeasureTheory.Lp E p μ)) (g : (MeasureTheory.Lp F q μ)) :
          ((lpPairing μ p q B) f) g = (x : α), (B (f x)) (g x) μ

          Heterogeneous scalar multiplication #

          While the previous section is nominally more general than this one, and indeed, we could use the constructions of the previous section to define the scalar multiplication herein, we would lose some slight generality as we would need to require that 𝕜 is a nontrivially normed field everywhere. Moreover, it would only simplify a few proofs.

          instance MeasureTheory.Lp.instHSMulSubtypeAEEqFunMemAddSubgroup {α : Type u_1} {𝕜 : Type u_3} {E : Type u_4} {m : MeasurableSpace α} {μ : Measure α} {p q r : ENNReal} [hpqr : p.HolderTriple q r] [NormedRing 𝕜] [NormedAddCommGroup E] [MulActionWithZero 𝕜 E] [IsBoundedSMul 𝕜 E] :
          HSMul (Lp 𝕜 p μ) (Lp E q μ) (Lp E r μ)

          Heterogeneous scalar multiplication of MeasureTheory.Lp functions by MeasureTheory.Lp functions when the exponents satisfy ENNReal.HolderTriple p q r.

          Equations
          theorem MeasureTheory.Lp.smul_def {α : Type u_1} {𝕜 : Type u_3} {E : Type u_4} {m : MeasurableSpace α} {μ : Measure α} {p q r : ENNReal} [hpqr : p.HolderTriple q r] [NormedRing 𝕜] [NormedAddCommGroup E] [MulActionWithZero 𝕜 E] [IsBoundedSMul 𝕜 E] {f : (Lp 𝕜 p μ)} {g : (Lp E q μ)} :
          f g = MemLp.toLp (f g)
          theorem MeasureTheory.Lp.coeFn_lpSMul {α : Type u_1} {𝕜 : Type u_3} {E : Type u_4} {m : MeasurableSpace α} {μ : Measure α} {p q r : ENNReal} [hpqr : p.HolderTriple q r] [NormedRing 𝕜] [NormedAddCommGroup E] [MulActionWithZero 𝕜 E] [IsBoundedSMul 𝕜 E] (f : (Lp 𝕜 p μ)) (g : (Lp E q μ)) :
          ↑(f g) =ᶠ[ae μ] f g
          theorem MeasureTheory.Lp.norm_smul_le {α : Type u_1} {𝕜 : Type u_3} {E : Type u_4} {m : MeasurableSpace α} {μ : Measure α} {p q r : ENNReal} [hpqr : p.HolderTriple q r] [NormedRing 𝕜] [NormedAddCommGroup E] [MulActionWithZero 𝕜 E] [IsBoundedSMul 𝕜 E] (f : (Lp 𝕜 p μ)) (g : (Lp E q μ)) :
          theorem MeasureTheory.Lp.smul_add {α : Type u_1} {𝕜 : Type u_3} {E : Type u_4} {m : MeasurableSpace α} {μ : Measure α} {p q r : ENNReal} [hpqr : p.HolderTriple q r] [NormedRing 𝕜] [NormedAddCommGroup E] [Module 𝕜 E] [IsBoundedSMul 𝕜 E] (f₁ f₂ : (Lp 𝕜 p μ)) (g : (Lp E q μ)) :
          (f₁ + f₂) g = f₁ g + f₂ g
          theorem MeasureTheory.Lp.add_smul {α : Type u_1} {𝕜 : Type u_3} {E : Type u_4} {m : MeasurableSpace α} {μ : Measure α} {p q r : ENNReal} [hpqr : p.HolderTriple q r] [NormedRing 𝕜] [NormedAddCommGroup E] [Module 𝕜 E] [IsBoundedSMul 𝕜 E] (f : (Lp 𝕜 p μ)) (g₁ g₂ : (Lp E q μ)) :
          f (g₁ + g₂) = f g₁ + f g₂
          @[simp]
          theorem MeasureTheory.Lp.smul_zero {α : Type u_1} {𝕜 : Type u_3} (E : Type u_4) {m : MeasurableSpace α} {μ : Measure α} {p : ENNReal} (q : ENNReal) {r : ENNReal} [hpqr : p.HolderTriple q r] [NormedRing 𝕜] [NormedAddCommGroup E] [Module 𝕜 E] [IsBoundedSMul 𝕜 E] (f : (Lp 𝕜 p μ)) :
          f 0 = 0
          @[simp]
          theorem MeasureTheory.Lp.zero_smul {α : Type u_1} (𝕜 : Type u_3) {E : Type u_4} {m : MeasurableSpace α} {μ : Measure α} (p : ENNReal) {q r : ENNReal} [hpqr : p.HolderTriple q r] [NormedRing 𝕜] [NormedAddCommGroup E] [Module 𝕜 E] [IsBoundedSMul 𝕜 E] (f : (Lp E q μ)) :
          0 f = 0
          @[simp]
          theorem MeasureTheory.Lp.smul_neg {α : Type u_1} {𝕜 : Type u_3} {E : Type u_4} {m : MeasurableSpace α} {μ : Measure α} {p q r : ENNReal} [hpqr : p.HolderTriple q r] [NormedRing 𝕜] [NormedAddCommGroup E] [Module 𝕜 E] [IsBoundedSMul 𝕜 E] (f : (Lp 𝕜 p μ)) (g : (Lp E q μ)) :
          f -g = -(f g)
          @[simp]
          theorem MeasureTheory.Lp.neg_smul {α : Type u_1} {𝕜 : Type u_3} {E : Type u_4} {m : MeasurableSpace α} {μ : Measure α} {p q r : ENNReal} [hpqr : p.HolderTriple q r] [NormedRing 𝕜] [NormedAddCommGroup E] [Module 𝕜 E] [IsBoundedSMul 𝕜 E] (f : (Lp 𝕜 p μ)) (g : (Lp E q μ)) :
          -f g = -(f g)
          theorem MeasureTheory.Lp.neg_smul_neg {α : Type u_1} {𝕜 : Type u_3} {E : Type u_4} {m : MeasurableSpace α} {μ : Measure α} {p q r : ENNReal} [hpqr : p.HolderTriple q r] [NormedRing 𝕜] [NormedAddCommGroup E] [Module 𝕜 E] [IsBoundedSMul 𝕜 E] (f : (Lp 𝕜 p μ)) (g : (Lp E q μ)) :
          -f -g = f g
          theorem MeasureTheory.Lp.smul_assoc {α : Type u_1} {𝕜' : Type u_2} {𝕜 : Type u_3} {E : Type u_4} {m : MeasurableSpace α} {μ : Measure α} {p q r : ENNReal} [hpqr : p.HolderTriple q r] [NormedRing 𝕜] [NormedAddCommGroup E] [Module 𝕜 E] [IsBoundedSMul 𝕜 E] [NormedRing 𝕜'] [Module 𝕜' E] [Module 𝕜' 𝕜] [IsBoundedSMul 𝕜' E] [IsBoundedSMul 𝕜' 𝕜] [IsScalarTower 𝕜' 𝕜 E] (c : 𝕜') (f : (Lp 𝕜 p μ)) (g : (Lp E q μ)) :
          (c f) g = c f g
          theorem MeasureTheory.Lp.smul_comm {α : Type u_1} {𝕜' : Type u_2} {𝕜 : Type u_3} {E : Type u_4} {m : MeasurableSpace α} {μ : Measure α} {p q r : ENNReal} [hpqr : p.HolderTriple q r] [NormedRing 𝕜] [NormedAddCommGroup E] [Module 𝕜 E] [IsBoundedSMul 𝕜 E] [NormedRing 𝕜'] [Module 𝕜' E] [Module 𝕜' 𝕜] [IsBoundedSMul 𝕜' E] [IsBoundedSMul 𝕜' 𝕜] [SMulCommClass 𝕜' 𝕜 E] (c : 𝕜') (f : (Lp 𝕜 p μ)) (g : (Lp E q μ)) :
          c f g = f c g