OAI/Geometry/SurfaceImmersion/Correction/SmoothingC1Approximation.lean

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3 declarations, 0 contain sorry, 0 declared as axioms

Uniform approximation of C1 coordinate maps by the existing smooth kernel.

  1. lemma OAI.ClosedSurfaceR4.FiniteOrderSmoothing.fderiv_smooth_C1 line 16
  2. theorem OAI.ClosedSurfaceR4.FiniteOrderSmoothing.smooth_uniform_approximation line 32

    Source documentation

    Uniform continuity suffices for uniform convergence of the signed finite-moment kernel. Positivity of the kernel is not required.

    theorem smooth_uniform_approximation (r : ℕ) {f : Base → E}
        (hf : UniformContinuous f) {ε : ℝ} (hε : 0 < ε) :
        ∃ η : ℝ, 0 < η ∧ ∀ s : ℝ, 0 < s → s < η →
          ∀ x : Base, ‖smooth r s f x-f x‖ ≤ ε := by
    …

    Mentions: OAI.ClosedSurfaceR4.FiniteOrderSmoothing.smooth

  3. theorem OAI.ClosedSurfaceR4.FiniteOrderSmoothing.smooth_C1_approximation line 85

    Source documentation

    Compactly supported C1 maps have smooth approximants converging uniformly both as maps and in their first derivatives.

    theorem smooth_C1_approximation (r : ℕ) {f : Base → E}
        (hf : ContDiff ℝ 1 f) (hfc : HasCompactSupport f) {ε : ℝ} (hε : 0 < ε) :
        ∃ η : ℝ, 0 < η ∧ ∀ s : ℝ, 0 < s → s < η →
          ContDiff ℝ ∞ (smooth r s f) ∧
          ∀ x, ‖smooth r s f x-f x‖ ≤ ε ∧
            ‖fderiv ℝ (smooth r s f) x-fderiv ℝ f x‖ ≤ ε := by
    …

    Mentions: OAI.ClosedSurfaceR4.FiniteOrderSmoothing.smooth