OAI/Geometry/RCD/Heat/LongAverageGaussian.lean

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Averaging a Gaussian above the averaging-ball scale

  1. theorem OAI.RegularPointCoordinates.kernelAverage_gaussian_above_scale line 20

    Source documentation

    When the heat length exceeds the averaging radius, a Gaussian at any averaging point gives a Gaussian at the fixed reference center.

    theorem kernelAverage_gaussian_above_scale {r t A B D : ℝ}
        (hr : 0 < r) (ht : 0 < t) (hA : 0 ≤ A) (hB : 0 ≤ B) (hD : 0 < D)
        (hrtime : r ^ 2 ≤ t) (x q z : X)
        (hfinite : μ (ball q r) ≠ ∞) (hvol : 0 < μ.real (ball q r))
        (hcenter : dist x q ≤ A * r)
        (hbound : ∀ y ∈ ball q r,
          ker t y z ≤ B * Real.exp (-(dist y z) ^ 2 / (D * t))) :
        kernelAverage μ ker t (ball q r) z ≤
          (B * Real.exp ((A + 1) ^ 2 / D)) *
            Real.exp (-(dist x z) ^ 2 / (2 * D * t)) := by
    …

    Mentions: OAI.RegularPointCoordinates.kernelAverage