OAI/Geometry/RCD/Heat/EuclideanRadialKernel.lean

GitHub source file

6 declarations, 0 contain sorry, 0 declared as axioms

Rescaled radial kernels and exact convolution normalization

  1. def OAI.RegularPointCoordinates.euclideanRadialKernel line 14
  2. theorem OAI.RegularPointCoordinates.euclideanRadialKernel_smooth line 17
  3. theorem OAI.RegularPointCoordinates.euclideanRadialKernel_support line 21
  4. theorem OAI.RegularPointCoordinates.euclideanRadialKernel_compact line 31
  5. theorem OAI.RegularPointCoordinates.convolution_radialKernel_eq line 37

    Source documentation

    Scaling the kernel produces precisely the dilation average, including its Euclidean volume factor.

    theorem convolution_radialKernel_eq (n : ℕ) (f : Euclidean n → ℝ) (p : Euclidean n)
        {r : ℝ} (hr : 0 < r) :
        (f ⋆[ContinuousLinearMap.mul ℝ ℝ,volume] euclideanRadialKernel n r) p =
          r^n*(∫ x, f (p+r • x)*euclideanRadialWeight n x) := by
    …

    Mentions: OAI.RegularPointCoordinates.Euclidean, OAI.RegularPointCoordinates.euclideanRadialKernel, OAI.RegularPointCoordinates.euclideanRadialWeight

  6. theorem OAI.RegularPointCoordinates.harmonic_convolution_radialKernel line 68

    Source documentation

    The radial mean theorem becomes an actual local convolution identity.

    theorem harmonic_convolution_radialKernel {n : ℕ} {f : Euclidean n → ℝ}
        (hf : ContDiff ℝ 2 f) (hfs : HasCompactSupport f) (p : Euclidean n)
        {R r : ℝ} (hR : 0 < R) (hr : 0 < r) (hrR : r < R)
        (hh : InnerProductSpace.HarmonicOnNhd f (ball p R)) :
        (f ⋆[ContinuousLinearMap.mul ℝ ℝ,volume] euclideanRadialKernel n r) p =
          (r^n*(∫ x, euclideanRadialWeight n x))*f p := by
    …

    Mentions: OAI.RegularPointCoordinates.Euclidean, OAI.RegularPointCoordinates.euclideanRadialKernel, OAI.RegularPointCoordinates.euclideanRadialWeight