OAI.ElasticityRegularity.quantitative_cutoff_gain: intermediate lemma from OpenAI, Global Uniqueness for the Smooth Isotropic Elasticity Inverse Problem

Proved

OAI.ElasticityRegularity.quantitative_cutoff_gain

by dbenbenn · Oct 26, 2026 · Mathlib 0df444a (Lean v4.33.1)

openai-math

An intermediate lemma of the split of OpenAI's proof of OAI.Elasticity.global_uniqueness, carved from OpenAI's openai/math development for this platform. The statement and its proof are OpenAI's (OpenAI, Global Uniqueness for the Smooth Isotropic Elasticity Inverse Problem, OpenAI Math Release, September 24, 2026, result family 372, github.com/openai/math, Apache License 2.0); in Lean it is the declaration OAI.ElasticityRegularity.quantitative_cutoff_gain of lean/OAI/MathematicalPhysics/Elasticity/CGO.lean at commit adc7f12, ported to Lean 4.33.1 and Mathlib 0df444a.

The statement, as published (namespace OAI.ElasticityRegularity, with open MeasureTheory TemperedDistribution, open scoped SchwartzMap LineDeriv Laplacian Real ENNReal BigOperators):

theorem quantitative_cutoff_gain (k : ℤ) {χ η : E → ℂ}
    (hχ : ContDiff ℝ (⊤ : ℕ∞) χ) (hcχ : HasCompactSupport χ)
    (hη : ContDiff ℝ (⊤ : ℕ∞) η) (hcη : HasCompactSupport η)
    (h1 : Set.EqOn η 1 (tsupport χ)) :
    ∃ C : ℝ, 0<C ∧ ∀ (u : 𝓢'(E,ℂ)) (f g : Lp ℂ 2 (volume : Measure E)),
      sobolevInjection (k : ℝ) f=smulLeftCLM ℂ η u →
      sobolevInjection ((k : ℝ)-1) g=smulLeftCLM ℂ η (Δ u) →
      ∃ q : Lp ℂ 2 (volume : Measure E),
        sobolevInjection ((k : ℝ)+1) q=smulLeftCLM ℂ χ u ∧
        ‖q‖ ≤ C*(‖f‖+‖g‖)

Definitions. The statement is written with OAI.ElasticityRegularity.sobolevInjection (definitions bundle OAIQ6El002 of this split).

Used by. The proof of OAI.ElasticityDistribution.scalar_principal_quantitative_gain of this split imports it.

Preamble

import Mathlib
import Definitions.Def_OAIQ6El002

Formal statement

section

attribute [-instance] _root_.OAI.ElasticityGeneralSlicing.cylinder_temperate
set_option linter.all false
set_option linter.unusedVariables false
set_option linter.unusedTactic false
set_option linter.unreachableTactic false

namespace OAI

noncomputable section

namespace ElasticityRegularity
open MeasureTheory TemperedDistribution
open scoped SchwartzMap LineDeriv Laplacian Real ENNReal BigOperators
variable {E : Type*} [NormedAddCommGroup E] [InnerProductSpace ℝ E]
  [FiniteDimensional ℝ E] [MeasurableSpace E] [BorelSpace E]

theorem quantitative_cutoff_gain (k : ℤ) {χ η : E → ℂ}
    (hχ : ContDiff ℝ (⊤ : ℕ∞) χ) (hcχ : HasCompactSupport χ)
    (hη : ContDiff ℝ (⊤ : ℕ∞) η) (hcη : HasCompactSupport η)
    (h1 : Set.EqOn η 1 (tsupport χ)) :
    ∃ C : ℝ, 0<C ∧ ∀ (u : 𝓢'(E,ℂ)) (f g : Lp ℂ 2 (volume : Measure E)),
      sobolevInjection (k : ℝ) f=smulLeftCLM ℂ η u →
      sobolevInjection ((k : ℝ)-1) g=smulLeftCLM ℂ η (Δ u) →
      ∃ q : Lp ℂ 2 (volume : Measure E),
        sobolevInjection ((k : ℝ)+1) q=smulLeftCLM ℂ χ u ∧
        ‖q‖ ≤ C*(‖f‖+‖g‖) := by
  sorry
end ElasticityRegularity

end

end OAI
end

Source

OpenAI, Global Uniqueness for the Smooth Isotropic Elasticity Inverse Problem, OpenAI Math Release, September 24, 2026, https://github.com/openai/math (result family 372; paper: https://github.com/openai/math/blob/adc7f1241b42e322a6451854ab7e4b4c146bf78a/preprints/Global-Uniqueness-for-the-Smooth-Isotropic-Elasticity-Inverse-Problem-September-24-2026/article.pdf; Apache License 2.0); Lean: https://github.com/openai/math/blob/adc7f1241b42e322a6451854ab7e4b4c146bf78a/lean/OAI/MathematicalPhysics/Elasticity/CGO.lean (declaration OAI.ElasticityRegularity.quantitative_cutoff_gain)

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