De Giorgi preiter on concentric Balls of ball Pos Part
DeGiorgi.deGiorgi_preiter_on_concentricBalls_of_ballPosPart
Project documentation
PDE-facing De Giorgi pre-iteration theorem on concentric balls. This now factors through the explicit cutoff-Sobolev bridge deGiorgi_cutoffSobolev_on_concentricBalls_of_ballPosPart instead of keeping the local Sobolev argument bundled into one monolithic proof.
Exact Lean statement
theorem deGiorgi_preiter_on_concentricBalls_of_ballPosPart
{u η : E → ℝ} {x₀ : E} {r s θ lam Cη : ℝ}
(hd : 2 < (d : ℝ))
(A : EllipticCoeff d (Metric.ball x₀ s))
(hr : 0 < r) (hrs : r < s)
(hsub : IsSubsolution A u)
(hu : MemW1pWitness 2 u (Metric.ball x₀ s))
(hwθ : MemW1pWitness 2 (positivePartSub u θ) (Metric.ball x₀ s))
(hθl : θ < lam)
(hη : ContDiff ℝ (⊤ : ℕ∞) η)
(hη_nonneg : ∀ x, 0 ≤ η x)
(hη_eq_one : ∀ x ∈ Metric.ball x₀ r, η x = 1)
(hη_bound : ∀ x, |η x| ≤ 1)
(hCη : 0 ≤ Cη)
(hη_grad_bound : ∀ x, ‖fderiv ℝ η x‖ ≤ Cη)
(hη_sub_ball : tsupport η ⊆ Metric.ball x₀ s) :
∫ x in Metric.ball x₀ r, |positivePartSub u lam x| ^ 2 ∂volume ≤
(C_gns d 2) ^ 2 * (8 * (ellipticityRatio A + 1) * Cη ^ 2) *
((((lam - θ) ^ 2)⁻¹ *
∫ x in Metric.ball x₀ s, |positivePartSub u θ x| ^ 2 ∂volume) ^ (2 / (d : ℝ))) *
∫ x in Metric.ball x₀ s, |positivePartSub u θ x| ^ 2 ∂volumeFormal artifact
Lean source
theorem deGiorgi_preiter_on_concentricBalls_of_ballPosPart {u η : E → ℝ} {x₀ : E} {r s θ lam Cη : ℝ} (hd : 2 < (d : ℝ)) (A : EllipticCoeff d (Metric.ball x₀ s)) (hr : 0 < r) (hrs : r < s) (hsub : IsSubsolution A u) (hu : MemW1pWitness 2 u (Metric.ball x₀ s)) (hwθ : MemW1pWitness 2 (positivePartSub u θ) (Metric.ball x₀ s)) (hθl : θ < lam) (hη : ContDiff ℝ (⊤ : ℕ∞) η) (hη_nonneg : ∀ x, 0 ≤ η x) (hη_eq_one : ∀ x ∈ Metric.ball x₀ r, η x = 1) (hη_bound : ∀ x, |η x| ≤ 1) (hCη : 0 ≤ Cη) (hη_grad_bound : ∀ x, ‖fderiv ℝ η x‖ ≤ Cη) (hη_sub_ball : tsupport η ⊆ Metric.ball x₀ s) : ∫ x in Metric.ball x₀ r, |positivePartSub u lam x| ^ 2 ∂volume ≤ (C_gns d 2) ^ 2 * (8 * (ellipticityRatio A + 1) * Cη ^ 2) * ((((lam - θ) ^ 2)⁻¹ * ∫ x in Metric.ball x₀ s, |positivePartSub u θ x| ^ 2 ∂volume) ^ (2 / (d : ℝ))) * ∫ x in Metric.ball x₀ s, |positivePartSub u θ x| ^ 2 ∂volume := by have hs : 0 < s := lt_trans hr hrs have hd_pos : 0 < (d : ℝ) := by linarith have hRatio_nonneg : 0 ≤ ellipticityRatio A := A.ellipticityRatio_nonneg have hCenergy_nonneg : 0 ≤ 8 * (ellipticityRatio A + 1) * Cη ^ 2 := by have hCη_sq_nonneg : 0 ≤ Cη ^ 2 := sq_nonneg Cη nlinarith have hθ_int : Integrable (fun x => |positivePartSub u θ x| ^ 2) (volume.restrict (Metric.ball x₀ s)) := by simpa [pow_two] using hwθ.memLp.integrable_sq have hIθ_nonneg : 0 ≤ ∫ x in Metric.ball x₀ s, |positivePartSub u θ x| ^ 2 ∂volume := by refine integral_nonneg ?_ intro x positivity obtain ⟨hwηθ, hsob⟩ := deGiorgi_cutoffSobolev_on_concentricBalls_of_ballPosPart (d := d) hd hr hrs hu hwθ hθl hη hη_nonneg hη_eq_one hη_bound hη_sub_ball let hwφ : MemW1pWitness 2 (deGiorgiCutoffTestGeneral η u θ) (Metric.ball x₀ s) := deGiorgiCutoffTestWitnessWeighted isOpen_ball hwθ hη (by norm_num) hCη hη_bound hη_grad_bound have hweighted : ∫ x in Metric.ball x₀ s, η x ^ 2 * ‖hwθ.weakGrad x‖ ^ 2 ∂volume ≤ (4 * ellipticityRatio A) * ∫ x in Metric.ball x₀ s, ‖fderiv ℝ η x‖ ^ 2 * |positivePartSub u θ x| ^ 2 ∂volume := by simpa [mul_assoc, mul_left_comm, mul_comm] using caccioppoli_weighted_on_ball_of_ballPosPart A hs hsub hu hwθ hη hη_nonneg hη_bound hCη hη_grad_bound hη_sub_ball have hgrad_bound_phi : ∫ x in Metric.ball x₀ s, ‖hwφ.weakGrad x‖ ^ 2 ∂volume ≤ (8 * (ellipticityRatio A + 1) * Cη ^ 2) * ∫ x in Metric.ball x₀ s, |positivePartSub u θ x| ^ 2 ∂volume := by simpa [hwφ] using deGiorgi_cutoff_gradient_bound_of_weighted (x₀ := x₀) (s := s) (u := u) (η := η) (k := θ) (Cη := Cη) (Cw := ellipticityRatio A) hRatio_nonneg hwθ hη hη_nonneg hη_bound hCη hη_grad_bound hweighted have hgrad_ae : hwηθ.weakGrad =ᵐ[volume.restrict (Metric.ball x₀ s)] hwφ.weakGrad := MemW1pWitness.ae_eq isOpen_ball hwηθ hwφ have hgrad_eq : ∫ x in Metric.ball x₀ s, ‖hwηθ.weakGrad x‖ ^ 2 ∂volume = ∫ x in Metric.ball x₀ s, ‖hwφ.weakGrad x‖ ^ 2 ∂volume := by refine integral_congr_ae ?_ filter_upwards [hgrad_ae] with x hx simp [hx] have henergy : ∫ x in Metric.ball x₀ s, ‖hwηθ.weakGrad x‖ ^ 2 ∂volume ≤ (8 * (ellipticityRatio A + 1) * Cη ^ 2) * ∫ x in Metric.ball x₀ s, |positivePartSub u θ x| ^ 2 ∂volume := by rw [hgrad_eq] exact hgrad_bound_phi haveI : IsFiniteMeasure (volume.restrict (Metric.ball x₀ s)) := by rw [isFiniteMeasure_restrict] exact measure_ball_lt_top.ne simpa [mul_assoc, mul_left_comm, mul_comm] using deGiorgi_preiter_of_energy (μ := volume.restrict (Metric.ball x₀ s)) (d := d) hd_pos (u := u) (θ := θ) (lam := lam) (Ilam := ∫ x in Metric.ball x₀ r, |positivePartSub u lam x| ^ 2 ∂volume) (Iθ := ∫ x in Metric.ball x₀ s, |positivePartSub u θ x| ^ 2 ∂volume) (G := ∫ x in Metric.ball x₀ s, ‖hwηθ.weakGrad x‖ ^ 2 ∂volume) (Csob := (C_gns d 2) ^ 2) (Cenergy := 8 * (ellipticityRatio A + 1) * Cη ^ 2) hθl (sq_nonneg _) hCenergy_nonneg hIθ_nonneg hθ_int hsob henergy (by rfl)- Project
- DeGiorgi
- License
- Apache-2.0
- Commit
- 4c1b3077d378
- Source
- DeGiorgi/DeGiorgiIteration/PreIteration.lean:982-1076
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Ae eq of tendsto e Lp Norm sub
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Source project: DeGiorgi
Person-level attribution pending.
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Person-level attribution pending.
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Source project: DeGiorgi
Person-level attribution pending.