OAI/Geometry/EinsteinFour/ScalarLpVariation.lean

GitHub source file

5 declarations, 0 contain sorry, 0 declared as axioms

Differentiation of the scalar p-moment along bounded directions. The base function need only belong to Lp, including at its zero set.

  1. theorem OAI.PositiveEinsteinFour.Geometry.scalarMoment_point_derivative line 18
  2. theorem OAI.PositiveEinsteinFour.Geometry.scalarMoment_derivative_bound line 28
  3. theorem OAI.PositiveEinsteinFour.Geometry.scalarLpMoment_hasDerivAt line 61

    Source documentation

    A bounded measurable direction differentiates the p-moment of an arbitrary Lp function. No nonvanishing or regularity assumption is placed on the latter.

    theorem scalarLpMoment_hasDerivAt {p : ℝ} (hp : 2 < p) {f b : X → ℝ}
        (hf : MemLp f (ENNReal.ofReal p) μ) (hb : AEStronglyMeasurable b μ)
        {B : ℝ} (hB : 0 ≤ B) (hbBound : ∀ᵐ x ∂μ, |b x| ≤ B) :
        Integrable (fun x => |f x| ^ (p - 2) * f x * b x) μ ∧
          HasDerivAt (fun t : ℝ => ∫ x, |f x + t * b x| ^ p ∂μ)
            (p * ∫ x, |f x| ^ (p - 2) * f x * b x ∂μ) 0 := by
    …
  4. theorem OAI.PositiveEinsteinFour.Geometry.scalarLpMoment_hasDerivAt_lp line 120

    Source documentation

    Lp-space version, ready for a weak variational equation.

    theorem scalarLpMoment_hasDerivAt_lp {p : ℝ} (hp : 2 < p)
        (f : Lp ℝ (ENNReal.ofReal p) μ) {b : X → ℝ}
        (hb : AEStronglyMeasurable b μ) {B : ℝ} (hB : 0 ≤ B)
        (hbBound : ∀ᵐ x ∂μ, |b x| ≤ B) :
        HasDerivAt (fun t : ℝ => ∫ x, |f x + t * b x| ^ p ∂μ)
          (p * ∫ x, |f x| ^ (p - 2) * f x * b x ∂μ) 0 :=
    …
  5. theorem OAI.PositiveEinsteinFour.Geometry.scalarLpMoment_hasDerivAt_continuous line 130

    Source documentation

    On a compact base every continuous, hence every smooth, test direction automatically satisfies the required domination.

    theorem scalarLpMoment_hasDerivAt_continuous [TopologicalSpace X]
        [OpensMeasurableSpace X] [CompactSpace X] {p : ℝ} (hp : 2 < p)
        {f : X → ℝ} (hf : MemLp f (ENNReal.ofReal p) μ) (b : C(X, ℝ)) :
        Integrable (fun x => |f x| ^ (p - 2) * f x * b x) μ ∧
          HasDerivAt (fun t : ℝ => ∫ x, |f x + t * b x| ^ p ∂μ)
            (p * ∫ x, |f x| ^ (p - 2) * f x * b x ∂μ) 0 :=
    …