Coarse-graining support: Support.Sobolev.W1p.InwardMollificationLp #
Imported from the Apache-2.0 CoarseGraining development at commit
c7ddd76c08ade64fed1b8d2ca51be14dfee8deb4.
Global L^p convergence of inward mollification #
This file combines the global approximate-identity theorem with strong continuity under the outward affine expansion. The result is independent of domain geometry and boundary conditions.
theorem
HCPolySupport.tendsto_eLpNorm_inwardMollification_sub_zero
{d : ℕ}
{ρ g : Vec d → ℝ}
{p : ENNReal}
(hρ : IsConvexApproxKernel ρ)
(hp1 : 1 ≤ p)
(hp : p ≠ ⊤)
(hg : MeasureTheory.MemLp g p MeasureTheory.volume)
(x0 : Vec d)
{r : ℝ}
(hr : 0 < r)
{ε : ℕ → ℝ}
(hε : Filter.Tendsto ε Filter.atTop (nhds 0))
(hε_nonneg : ∀ (n : ℕ), 0 ≤ ε n)
(hε_pos : ∀ᶠ (n : ℕ) in Filter.atTop, 0 < ε n)
:
Filter.Tendsto (fun (n : ℕ) => MeasureTheory.eLpNorm (inwardMollification ρ g x0 r (ε n) - g) p MeasureTheory.volume)
Filter.atTop (nhds 0)
Inward mollification converges strongly to its input in every finite
L^p, 1 ≤ p < ∞, on the whole Euclidean space.
theorem
HCPolySupport.tendsto_eLpNorm_one_add_mul_inwardMollification_sub_zero
{d : ℕ}
{ρ g : Vec d → ℝ}
{p : ENNReal}
(hρ : IsConvexApproxKernel ρ)
(hp1 : 1 ≤ p)
(hp : p ≠ ⊤)
(hg : MeasureTheory.MemLp g p MeasureTheory.volume)
(x0 : Vec d)
{r : ℝ}
(hr : 0 < r)
{ε : ℕ → ℝ}
(hε : Filter.Tendsto ε Filter.atTop (nhds 0))
(hε_nonneg : ∀ (n : ℕ), 0 ≤ ε n)
(hε_pos : ∀ᶠ (n : ℕ) in Filter.atTop, 0 < ε n)
:
Filter.Tendsto
(fun (n : ℕ) =>
MeasureTheory.eLpNorm (fun (x : Vec d) => (1 + ε n) * inwardMollification ρ g x0 r (ε n) x - g x) p
MeasureTheory.volume)
Filter.atTop (nhds 0)
The scalar factor produced by differentiating the affine pullback does not
alter strong finite-L^p convergence of inward mollification.