All proofs
Project-declaredLean 4.29.0-rc6 · mathlib@5c8398df5281

Linfty subsolution Moser two

DeGiorgi.linfty_subsolution_Moser_two

Plain-language statement

The p = 2 anchor for Chapter 06 is already available from Chapter 05. This is the exact normalized De Giorgi unit-ball estimate rewritten in the Chapter 06 a.e. power-bound format. It is the base case that the later Moser iteration should strictly improve from p = 2 to arbitrary p > 1.

Exact Lean statement

theorem linfty_subsolution_Moser_two
    (hd : 2 < (d : ℝ))
    (A : NormalizedEllipticCoeff d (Metric.ball (0 : E) 1))
    {u : E → ℝ}
    (hsub : IsSubsolution A.1 u)
    (hposInt :
      IntegrableOn (fun x => |max (u x) 0| ^ 2)
        (Metric.ball (0 : E) 1) volume) :
    ∀ᵐ x ∂(volume.restrict (Metric.ball (0 : E) (1 / 2 : ℝ))),
      |max (u x) 0| ^ 2 ≤
        C_Moser d * A.1.Λ ^ ((d : ℝ) / 2) *
          (2 / (2 - 1 : ℝ)) ^ (d : ℝ) *
          ∫ x in Metric.ball (0 : E) 1, |max (u x) 0| ^ 2 ∂volume

Formal artifact

Lean source

Canonical source
Full Lean sourceLean 4
theorem linfty_subsolution_Moser_two    (hd : 2 < (d : ))    (A : NormalizedEllipticCoeff d (Metric.ball (0 : E) 1))    {u : E  }    (hsub : IsSubsolution A.1 u)    (hposInt :      IntegrableOn (fun x => |max (u x) 0| ^ 2)        (Metric.ball (0 : E) 1) volume) :    ᵐ x ∂(volume.restrict (Metric.ball (0 : E) (1 / 2 : ))),      |max (u x) 0| ^ 2         C_Moser d * A.1^ ((d : ) / 2) *          (2 / (2 - 1 : )) ^ (d : ) *          ∫ x in Metric.ball (0 : E) 1, |max (u x) 0| ^ 2 ∂volume := by  let I₂ :  := ∫ x in Metric.ball (0 : E) 1, |max (u x) 0| ^ 2 ∂volume  let c :  := C_DeGiorgi_subsolution_normalized d * A.1^ ((d : ) / 4)  have hI₂_nonneg : 0  I₂ := by    dsimp [I₂]    refine integral_nonneg ?_    intro x    positivity  have hc_nonneg : 0  c := by    have hCDG_nonneg : 0  C_DeGiorgi_subsolution_normalized d := by      dsimp [C_DeGiorgi_subsolution_normalized]      exact        (C_DeGiorgiSmallness_pos (d := d)          (K_DeGiorgi_subsolution_normalized_pos (d := d))).le    dsimp [c]    exact mul_nonneg      hCDG_nonneg      (Real.rpow_nonneg A.1.Λ_nonneg _)  filter_upwards    [linfty_subsolution_DeGiorgi_normalized (d := d) hd A hsub hposInt]    with x hx  have hx_nonneg : 0  max (u x) 0 := by    positivity  have hsq :      |max (u x) 0| ^ 2  c ^ 2 * I₂ := by    have hx' : max (u x) 0  c * Real.sqrt I₂ := hx    have hrhs_nonneg : 0  c * Real.sqrt I₂ := by      exact mul_nonneg hc_nonneg (Real.sqrt_nonneg I₂)    have hsq' : (max (u x) 0) ^ 2  (c * Real.sqrt I₂) ^ 2 := by      nlinarith    calc      |max (u x) 0| ^ 2 = (max (u x) 0) ^ 2 := by        rw [abs_of_nonneg hx_nonneg]      _  (c * Real.sqrt I₂) ^ 2 := hsq'      _ = c ^ 2 * I₂ := by        rw [mul_pow, Real.sq_sqrt hI₂_nonneg]  have hconst :      c ^ 2 * I₂         C_Moser d * A.1^ ((d : ) / 2) *          (2 / (2 - 1 : )) ^ (d : ) * I₂ := by    have hbase :        c ^ 2           C_Moser d * A.1^ ((d : ) / 2) *            (2 / (2 - 1 : )) ^ (d : ) := by      have hpow :          (A.1^ ((d : ) / 4)) ^ 2 = A.1^ ((d : ) / 2) := by        rw [pow_two,  Real.rpow_add A.1.Λ_pos]        ring_nf      calc        c ^ 2            = (C_DeGiorgi_subsolution_normalized d) ^ 2 *                A.1^ ((d : ) / 2) := by                  dsimp [c]                  rw [mul_pow, hpow]        _  C_Moser d * A.1^ ((d : ) / 2) := by            exact mul_le_mul_of_nonneg_right              (C_DeGiorgi_subsolution_normalized_sq_le_C_Moser (d := d))              (Real.rpow_nonneg A.1.Λ_nonneg _)        _  C_Moser d * A.1^ ((d : ) / 2) *              (2 / (2 - 1 : )) ^ (d : ) := by            have hleft_nonneg : 0  C_Moser d * A.1^ ((d : ) / 2) := by              exact mul_nonneg                (le_trans (by norm_num : (0 : )  1) (one_le_C_Moser (d := d)))                (Real.rpow_nonneg A.1.Λ_nonneg _)            have hone : (1 : )  (2 / (2 - 1 : )) ^ (d : ) := by              have hbase : (1 : )  2 / (2 - 1 : ) := by norm_num              have hd_nonneg : 0  (d : ) := by exact_mod_cast Nat.zero_le d              exact Real.one_le_rpow hbase hd_nonneg            simpa [mul_assoc] using              (mul_le_mul_of_nonneg_left hone hleft_nonneg)    exact mul_le_mul_of_nonneg_right hbase hI₂_nonneg  exact le_trans hsq (by    simpa [I₂] using hconst)
Project
DeGiorgi
License
Apache-2.0
Commit
4c1b3077d378
Source
DeGiorgi/MoserIteration/Linfty.lean:396-480

Reuse this declaration

Bring the exact result into your workflow

The import identifies the source module. Your project still needs the pinned package dependency shown on this page.

What this badge means

This completion status comes from the project or community source. It has not yet been represented here as an independent rebuild and axiom audit.

Continue in this project

Related declarations

Project-declaredLean 4.29.0-rc6

Ae eq of tendsto e Lp Norm sub

BareFunction.ae_eq_of_tendsto_eLpNorm_sub

Plain-language statement

Lp limit uniqueness: if f_n → g₁ and f_n → g₂ in eLpNorm, then g₁ =ᵐ g₂.

partial differential equationsregularity theoryanalysis

Source project: DeGiorgi

Person-level attribution pending.

View proof record
Project-declaredLean 4.29.0-rc6

E Lp Norm pi le sum component

BareFunction.eLpNorm_pi_le_sum_component

Plain-language statement

Vector eLpNorm ≤ sum of component eLpNorms for Pi-valued functions. Uses eLpNorm_mono_real for the pointwise bound together with eLpNorm_sum_le for ℝ-valued functions, avoiding Pi instance synthesis.

partial differential equationsregularity theoryanalysis

Source project: DeGiorgi

Person-level attribution pending.

View proof record
Project-declaredLean 4.29.0-rc6

Mem Lp of tendsto e Lp Norm

BareFunction.memLp_of_tendsto_eLpNorm

Plain-language statement

If f n → g in eLpNorm and each f n ∈ Lp, then g ∈ Lp, provided g is AEStronglyMeasurable. Avoids the Lp type entirely. The key observation: eLpNorm (f n - g) → 0 means eLpNorm (f N - g) < 1 for some N. Then eLpNorm g ≤ eLpNorm (f N - g) + eLpNorm (f N) < ∞.

partial differential equationsregularity theoryanalysis

Source project: DeGiorgi

Person-level attribution pending.

View proof record