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Project-declaredLean 4.29.0-rc6 · mathlib@5c8398df5281

Linfty subsolution De Giorgi ae of unit Ball height bound

DeGiorgi.linfty_subsolution_DeGiorgi_ae_of_unitBall_height_bound

Plain-language statement

Height-threshold version of the De Giorgi endpoint. Once the PDE-facing one-step estimate is supplied, a lower bound for lamStar of the form C(d,K) * sqrt(∫_{B₁} (u₊)^2) yields the a.e. half-ball L∞ bound.

Exact Lean statement

theorem linfty_subsolution_DeGiorgi_ae_of_unitBall_height_bound
    {u : E → ℝ} {x₀ : E} {K lamStar : ℝ}
    (hd : 2 < (d : ℝ))
    (hK : 0 < K) (hLamStar : 0 < lamStar)
    (hposInt :
      IntegrableOn (fun x => |max (u x) 0| ^ 2)
        (Metric.ball x₀ 1) volume)
    (hStarInt :
      IntegrableOn (fun x => |positivePartSub u lamStar x| ^ 2)
        (Metric.ball x₀ (1 / 2 : ℝ)) volume)
    (hAint :
      ∀ n,
        IntegrableOn (fun x => |positivePartSub u (deGiorgiLevel lamStar n) x| ^ 2)
          (Metric.ball x₀ (deGiorgiRadius n)) volume)
    (hpre :
      ∀ n,
        deGiorgiEnergySeq u x₀ lamStar (n + 1) ≤
          K / ((deGiorgiRadius n - deGiorgiRadius (n + 1)) ^ 2 *
            (deGiorgiLevel lamStar (n + 1) - deGiorgiLevel lamStar n) ^ (4 / (d : ℝ))) *
          deGiorgiEnergySeq u x₀ lamStar n ^ (1 + 2 / (d : ℝ)))
    (hheight :
      C_DeGiorgiSmallness d K *
        Real.sqrt (∫ x in Metric.ball x₀ 1, |max (u x) 0| ^ 2 ∂volume) ≤
          lamStar) :
    ∀ᵐ x ∂(volume.restrict (Metric.ball x₀ (1 / 2 : ℝ))),
      max (u x) 0 ≤ lamStar

Formal artifact

Lean source

Canonical source
Full Lean sourceLean 4
theorem linfty_subsolution_DeGiorgi_ae_of_unitBall_height_bound    {u : E  } {x₀ : E} {K lamStar : }    (hd : 2 < (d : ))    (hK : 0 < K) (hLamStar : 0 < lamStar)    (hposInt :      IntegrableOn (fun x => |max (u x) 0| ^ 2)        (Metric.ball x₀ 1) volume)    (hStarInt :      IntegrableOn (fun x => |positivePartSub u lamStar x| ^ 2)        (Metric.ball x₀ (1 / 2 : )) volume)    (hAint :       n,        IntegrableOn (fun x => |positivePartSub u (deGiorgiLevel lamStar n) x| ^ 2)          (Metric.ball x₀ (deGiorgiRadius n)) volume)    (hpre :       n,        deGiorgiEnergySeq u x₀ lamStar (n + 1)           K / ((deGiorgiRadius n - deGiorgiRadius (n + 1)) ^ 2 *            (deGiorgiLevel lamStar (n + 1) - deGiorgiLevel lamStar n) ^ (4 / (d : ))) *          deGiorgiEnergySeq u x₀ lamStar n ^ (1 + 2 / (d : )))    (hheight :      C_DeGiorgiSmallness d K *        Real.sqrt (∫ x in Metric.ball x₀ 1, |max (u x) 0| ^ 2 ∂volume)           lamStar) :    ᵐ x ∂(volume.restrict (Metric.ball x₀ (1 / 2 : ))),      max (u x) 0  lamStar := by  have hI₀_nonneg :      0  ∫ x in Metric.ball x₀ 1, |max (u x) 0| ^ 2 ∂volume := by    refine integral_nonneg ?_    intro x    positivity  have hsmall0 :      ∫ x in Metric.ball x₀ 1, |max (u x) 0| ^ 2 ∂volume         (deGiorgiRecurrenceCoeff d K lamStar) ^ (-(1 : ) / (2 / (d : ))) *          (deGiorgiRecurrenceBase d) ^ (-(1 : ) / (2 / (d : )) ^ 2) :=    deGiorgi_initial_energy_small_of_height_bound hK hLamStar hI₀_nonneg hheight  exact linfty_subsolution_DeGiorgi_ae_of_unitBall_initial_energy_smallness    hd hK hLamStar hposInt hStarInt hAint hpre hsmall0
Project
DeGiorgi
License
Apache-2.0
Commit
4c1b3077d378
Source
DeGiorgi/DeGiorgiIteration/Linfty.lean:1121-1158

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