OAI/Geometry/RCD/Heat/HeatTransitionDecay.lean

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3 declarations, 0 contain sorry, 0 declared as axioms

Gaussian decay of the actual transition mass between separated sets

The estimate is a consequence of the weighted Cheeger semigroup bound.

  1. theorem OAI.RegularPointCoordinates.indicatorConstLp_norm_eq_sqrt line 19
  2. theorem OAI.RegularPointCoordinates.NoncollapsedRCD.heatRadonMeasure_set_pair line 32
  3. theorem OAI.RegularPointCoordinates.NoncollapsedRCD.heatRadonMeasure_separated_sets line 57

    Source documentation

    The sharp Davies exponent for transition mass between a source set inside a ball and an observation set outside a larger concentric ball.

    theorem heatRadonMeasure_separated_sets (t : ℝ) (ht : 0 < t)
        {A B : Set X} (hA : MeasurableSet A) (hB : MeasurableSet B)
        (hAf : hausdorff n X A ≠ ∞) (hBf : hausdorff n X B ≠ ∞)
        (q : X) {r R : ℝ} (hnear : ∀ x ∈ A, dist q x ≤ r)
        (hfar : ∀ x ∈ B, R ≤ dist q x) (hrR : r ≤ R) :
        (∫ x in B, (hX.heatRadonMeasure hn p t ht x).real A ∂hausdorff n X) ≤
          Real.exp (-(R-r)^2 / (4*t)) *
            Real.sqrt ((hausdorff n X).real A) * Real.sqrt ((hausdorff n X).real B) := by
    …

    Mentions: OAI.RegularPointCoordinates.hausdorff