OAI/Geometry/RCD/Sobolev/LocalGradientRepresentative.lean

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2 declarations, 0 contain sorry, 0 declared as axioms

Local bounded gradients and Lipschitz representatives

  1. theorem OAI.RegularPointCoordinates.NoncollapsedRCD.local_average_bound_of_gradient line 18

    Source documentation

    Transport between small balls controls their averages by the weak upper gradient, with no volume-comparison factor.

    theorem NoncollapsedRCD.local_average_bound_of_gradient
        (K : ℝ) (n : ℕ) (hn : 2 ≤ n) (hX : NoncollapsedRCD K n X)
        {u G : Lp ℝ 2 (hausdorff n X)} (hG : IsRelaxedSlope (hausdorff n X) u G)
        (L : ℝ≥0) {p : X} {R : ℝ} (hR : 0 < R)
        (hGb : ∀ᵐ x ∂(hausdorff n X).restrict (ball p (8 * R)), G x ≤ L)
        (x y : X) (hx : x ∈ closedBall p R) (hy : y ∈ closedBall p R)
        (r : ℝ) (hr : 0 < r) (hrR : r ≤ R) :
        |(⨍ z in closedBall x r, u z ∂hausdorff n X)-
          (⨍ z in closedBall y r, u z ∂hausdorff n X)| ≤ L*(dist x y+2*r) := by
    …

    Mentions: OAI.RegularPointCoordinates.NoncollapsedRCD, OAI.RegularPointCoordinates.hausdorff, OAI.RegularPointCoordinates.IsRelaxedSlope

  2. theorem OAI.RegularPointCoordinates.NoncollapsedRCD.local_lipschitz_representative line 103

    Source documentation

    Differentiation of local ball averages gives a sharp Lipschitz representative on the inner ball. No amplitude bound is needed.

    theorem NoncollapsedRCD.local_lipschitz_representative
        {K : ℝ} {n : ℕ} (hX : NoncollapsedRCD K n X) (hn : 2 ≤ n)
        {u G : Lp ℝ 2 (hausdorff n X)} (hG : IsRelaxedSlope (hausdorff n X) u G)
        (L : ℝ≥0) {p : X} {R : ℝ} (hR : 0 < R)
        (hGb : ∀ᵐ x ∂(hausdorff n X).restrict (ball p (8 * R)), G x ≤ L) :
        ∃ v : X → ℝ, LipschitzWith L v ∧
          u =ᵐ[(hausdorff n X).restrict (closedBall p R)] v := by
    …

    Mentions: OAI.RegularPointCoordinates.NoncollapsedRCD, OAI.RegularPointCoordinates.hausdorff, OAI.RegularPointCoordinates.IsRelaxedSlope