OAI/Geometry/EinsteinFour/ScalarPoissonKernelLocalRegularity.lean

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Small-coefficient regularity applies to an existing L2 distributional solution: construct an H2 solution, then identify the two using the actual formal-transpose uniqueness theorem.

  1. theorem OAI.PositiveEinsteinFour.Geometry.scalar_coordinate_sub line 21
  2. theorem OAI.PositiveEinsteinFour.Geometry.scalarPerturbedOperator_sub line 26
  3. theorem OAI.PositiveEinsteinFour.Geometry.scalarSchwartz_Linf_bound line 34
  4. theorem OAI.PositiveEinsteinFour.Geometry.scalar_small_elliptic_gain_two line 43

    Source documentation

    This is regularity of the given solution, not only existence of a new regular solution. All smallness assumptions concern the actual coefficient functions and their first two derivatives.

    theorem scalar_small_elliptic_gain_two
        (a : Fin 4 → Fin 4 → S) (b : Fin 4 → S) (δ : ℝ) (hδ : 0 ≤ δ)
        (ha : ∀ i j x, ‖a i j x‖ ≤ δ)
        (ha1 : ∀ i j k x, ‖D k (a i j) x‖ ≤ δ)
        (ha2 : ∀ i j k l x, ‖D k (D l (a i j)) x‖ ≤ δ)
        (hb : ∀ i x, ‖b i x‖ ≤ δ)
        (hb1 : ∀ i k x, ‖D k (b i) x‖ ≤ δ)
        (hsmall : (16 * (2 * Real.pi) ^ 2 + 36 * (2 * Real.pi) + 20) * δ < 1)
        (u f : L2) (hu : scalarPerturbedOperator a b (u : 𝓢'(V, ℂ)) = (f : 𝓢'(V, ℂ))) :
        MemSobolev 2 2 (u : 𝓢'(V, ℂ)) := by
    …

    Mentions: OAI.PositiveEinsteinFour.Geometry.scalarPerturbedOperator