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ASTIS mathematical exposition

Bochner energy under the actual reflected conditional Gibbs kernel

AutoSamplingTheory.ExampleCases.ProximalBPS.ConditionalBochner.conditional_bochner_energy · theorem · Teaching coverage

Statement

For the actual Gibbs-Gaussian augmentation there are common Markov kernels R,S: R disintegrates the swapped joint law and S_y is the reflected pushforward of R_y. Every S_y is normalized exp(-W_y) times volume, W_y(u)=V((y+u)/2)+norm(u-y)^2/(8 eta), with W_y C2 and finite strictly positive normalizer. For every smooth compactly supported f, the square of L_y f, squared gradient, coordinate Hessian-square term and genuine conditional curvature term are integrable under this same S_y. The exact normalized Bochner identity holds, and the square-generator energy bounds ((alpha+eta inverse)/4) times the gradient energy.

\[\int(L_yf)^2\,dS_y=\int H_f\,dS_y+\int D^2W_y[\nabla f,\nabla f]\,dS_y\ge\frac{\alpha+\eta^{-1}}4\int\|\nabla f\|^2\,dS_y.\]

All objects and hypotheses

  • E is finite-dimensional real inner-product with Borel structure and canonical volume, including dimension zero. V:E->R is C2.
  • Alpha,beta are finite nonnegative real parameters with explicit 0<alpha<=beta and genuine alpha/beta Hessian quadratic-form bounds on V.
  • Eta>0 and beta eta<=1 are retained from the ConditionalScoreDomain parent interface. The upper scale and upper curvature restrictions are not needed by the abstract Bochner identity; they are not removed from this conditional consumer.
  • Mu is volume tilted by -V; J is the law of (X,X+sqrt(eta)Z) from independent X~mu and standard Gaussian Z. The same constructed R,S work for every y and every smooth compactly supported f.
  • No probability, conditional density, global normalizer, integrability, integration-by-parts or Poincare premise is silently added; they are derived where claimed.

Mathematical proof

1. Keep one actual conditional kernel

Use ConditionalScoreDomain to obtain common R,S, their Markov properties, disintegration and reflected pushforward. For each y it provides exactly S_y=volume tilted by -W_y, W_y C2 and the genuine lower curvature (alpha+eta inverse)/4. Do not replace S_y by an unrelated measure with an assumed curvature inequality.

\[S_y=(x\mapsto2x-y)_\#R_y=Z_y^{-1}e^{-W_y(u)}\,du.\]
Corresponding Lean step

conditional_curvature_and_score_domain supplies the same existential witnesses; the consumer retains hR,hS,hcond,hSR,hSy and hcurv.

2. Prove the global normalizer is finite and positive

The shared compact-test identity alone cannot prove global weight integrability. Instead, S_y is already an actual probability measure and equals the tilt. If exp(-W_y) were not integrable, Mathlib tilt would be the zero measure, contradicting S_y(univ)=1. Thus the weight is integrable. Its pointwise strict positivity and nonzero volume make Z_y strictly positive. This rules out a totalized zero-measure normalization.

\[0<Z_y:=\int e^{-W_y(u)}\,du<\infty.\]
Corresponding Lean step

hweight contradicts tilted_of_not_integrable using the Markov probability mass. integral_exp_pos gives hZ before any normalized inequality is transferred.

3. Transport the full identity and every integral domain

Apply the actual shared Bochner theorem to W_y and f. It supplies all four weighted Integrable facts and the raw identity. The tilted-integrability equivalence transfers each fact to this same S_y. For every integrand g, the exact tilted integral equals Z_y inverse times the weighted volume integral, so multiplying the raw identity gives the normalized identity.

\[\int g\,dS_y=Z_y^{-1}\int e^{-W_y}g,\qquad\int(L_yf)^2\,dS_y=\int H_f\,dS_y+\int C_f\,dS_y.\]
Corresponding Lean step

integrated_bochner_identity is a genuine public shared theorem call. hI uses integrable_tilted_iff only after hweight; htilt uses integral_tilted and scalar integral algebra.

4. Use the actual conditional curvature constant

Apply the shared curvature-energy consequence to the inherited genuine Hessian lower bound, then multiply by positive Z_y inverse. This yields precisely (alpha+eta inverse)/4 times the S_y gradient energy. It remains a compact-test square-generator estimate. Constructing a weighted closed core/range or resolvent and extending to noncompact scores are still necessary before claiming conditional Poincare or score variance.

\[\frac{\alpha+\eta^{-1}}4\int\|\nabla f\|^2\,dS_y\le\int(L_yf)^2\,dS_y.\]
Corresponding Lean step

The final calc applies hbound to hcurv and uses inv_nonneg.mpr hZ.le; no variance or spectral-gap theorem is assumed.

Lean statement · conditional_bochner_energy

Common actual kernels, density and finite positive normalizer precede the universal compact-test integrability, identity and exact energy inequality.

Braces mark parameters Lean can infer; square brackets request structures such as a measurable space or probability measure. Named hypotheses are mathematical premises, not facts established by this declaration. Section parameters are described in the mathematical hypotheses above; the module link retains their exact source context.

theorem conditional_bochner_energy {E : Type*} [NormedAddCommGroup E] [InnerProductSpace ℝ E]
    [FiniteDimensional ℝ E] [MeasurableSpace E] [BorelSpace E]
    {V : E → ℝ} {α β : NNReal} {η : ℝ}
    (hα : 0 < (α:ℝ)) (hαβ : α ≤ β) (hV : ContDiff ℝ 2 V)
    (hH : ∀ x v : E, (α:ℝ)*‖v‖^2 ≤ (fderiv ℝ (fderiv ℝ V) x v) v ∧
      (fderiv ℝ (fderiv ℝ V) x v) v ≤ (β:ℝ)*‖v‖^2)
    (hη : 0 < η) (hβη : (β:ℝ)*η ≤ 1) :
    let μ := (volume : Measure E).tilted (fun x => -V x)
    let J := Measure.map (fun p : E × E => (p.1,p.1+Real.sqrt η • p.2)) (μ.prod (stdGaussian E))
    let W := fun y u : E => V ((1/2:ℝ) • (y+u)) + ‖u-y‖^2/(8*η)
    ∃ R S : Kernel E E, IsMarkovKernel R ∧ IsMarkovKernel S ∧
      (J.map Prod.swap).IsCondKernel R ∧
      (∀ y, S y = (R y).map (fun x => (2:ℝ) • x-y)) ∧
      ∀ y, S y = (volume : Measure E).tilted (fun u => -W y u) ∧
        ContDiff ℝ 2 (W y) ∧ Integrable (fun u => Real.exp (-W y u)) ∧
        0 < (∫ u, Real.exp (-W y u)) ∧
        ∀ f : E → ℝ, ContDiff ℝ ∞ f → HasCompactSupport f →
          let L := fun u => Laplacian.laplacian f u - inner ℝ (gradient (W y) u) (gradient f u)
          let H := fun u => ∑ i, ‖gradient (fun z => fderiv ℝ f z ((stdOrthonormalBasis ℝ E) i)) u‖^2
          let C := fun u => fderiv ℝ (fderiv ℝ (W y)) u (gradient f u) (gradient f u)
          Integrable (fun u => (L u)^2) (S y) ∧
          Integrable (fun u => ‖gradient f u‖^2) (S y) ∧
          Integrable H (S y) ∧ Integrable C (S y) ∧
          (∫ u, (L u)^2 ∂S y) = (∫ u, H u ∂S y) + ∫ u, C u ∂S y ∧
          (((α:ℝ)+1/η)/4) * (∫ u, ‖gradient f u‖^2 ∂S y) ≤ ∫ u, (L u)^2 ∂S y

Exact module and namespace context

Lean proof · conditional_bochner_energy

Reuse the genuine conditional construction and the full shared Bochner identity; derive the normalizer from actual probability and transfer all integrals exactly.

Braces mark parameters Lean can infer; square brackets request structures such as a measurable space or probability measure. Named hypotheses are mathematical premises, not facts established by this declaration. Section parameters are described in the mathematical hypotheses above; the module link retains their exact source context.

theorem conditional_bochner_energy {E : Type*} [NormedAddCommGroup E] [InnerProductSpace ℝ E]
    [FiniteDimensional ℝ E] [MeasurableSpace E] [BorelSpace E]
    {V : E → ℝ} {α β : NNReal} {η : ℝ}
    (hα : 0 < (α:ℝ)) (hαβ : α ≤ β) (hV : ContDiff ℝ 2 V)
    (hH : ∀ x v : E, (α:ℝ)*‖v‖^2 ≤ (fderiv ℝ (fderiv ℝ V) x v) v ∧
      (fderiv ℝ (fderiv ℝ V) x v) v ≤ (β:ℝ)*‖v‖^2)
    (hη : 0 < η) (hβη : (β:ℝ)*η ≤ 1) :
    let μ := (volume : Measure E).tilted (fun x => -V x)
    let J := Measure.map (fun p : E × E => (p.1,p.1+Real.sqrt η • p.2)) (μ.prod (stdGaussian E))
    let W := fun y u : E => V ((1/2:ℝ) • (y+u)) + ‖u-y‖^2/(8*η)
    ∃ R S : Kernel E E, IsMarkovKernel R ∧ IsMarkovKernel S ∧
      (J.map Prod.swap).IsCondKernel R ∧
      (∀ y, S y = (R y).map (fun x => (2:ℝ) • x-y)) ∧
      ∀ y, S y = (volume : Measure E).tilted (fun u => -W y u) ∧
        ContDiff ℝ 2 (W y) ∧ Integrable (fun u => Real.exp (-W y u)) ∧
        0 < (∫ u, Real.exp (-W y u)) ∧
        ∀ f : E → ℝ, ContDiff ℝ ∞ f → HasCompactSupport f →
          let L := fun u => Laplacian.laplacian f u - inner ℝ (gradient (W y) u) (gradient f u)
          let H := fun u => ∑ i, ‖gradient (fun z => fderiv ℝ f z ((stdOrthonormalBasis ℝ E) i)) u‖^2
          let C := fun u => fderiv ℝ (fderiv ℝ (W y)) u (gradient f u) (gradient f u)
          Integrable (fun u => (L u)^2) (S y) ∧
          Integrable (fun u => ‖gradient f u‖^2) (S y) ∧
          Integrable H (S y) ∧ Integrable C (S y) ∧
          (∫ u, (L u)^2 ∂S y) = (∫ u, H u ∂S y) + ∫ u, C u ∂S y ∧
          (((α:ℝ)+1/η)/4) * (∫ u, ‖gradient f u‖^2 ∂S y) ≤ ∫ u, (L u)^2 ∂S y := by
  obtain ⟨R,S,hR,hS,hcond,hSR,hfiber⟩ :=
    ConditionalScoreDomain.conditional_curvature_and_score_domain hα hαβ hV hH hη hβη
  let _ : IsMarkovKernel S := hS
  dsimp only
  refine ⟨R,S,hR,hS,hcond,hSR,?_⟩
  intro y
  let W := fun u : E => V ((1/2:ℝ) • (y+u)) + ‖u-y‖^2/(8*η)
  obtain ⟨hSy,hWC,_,_,hcurv,_,_⟩ := hfiber y
  change S y = (volume : Measure E).tilted (fun u => -W u) at hSy
  have hweight : Integrable (fun u => Real.exp (-W u)) := by
    by_contra hn
    have hz : S y = 0 := hSy.trans (tilted_of_not_integrable hn)
    have hu := measure_univ (μ := S y)
    rw [hz] at hu
    norm_num at hu
  have hZ : 0 < ∫ u, Real.exp (-W u) := integral_exp_pos hweight
  refine ⟨hSy,hWC,hweight,hZ,?_⟩
  intro f hf hc
  obtain ⟨hL,hG,hHess,hC,hidentity,hbound⟩ :=
    WeightedBochner.integrated_bochner_identity W f hWC hf hc
  have hI (g : E → ℝ) (hg : Integrable (fun u => Real.exp (-W u)*g u)) :
      Integrable g (S y) := by
    rw [hSy]
    exact (integrable_tilted_iff hweight g).mpr (by simpa only [smul_eq_mul] using hg)
  have htilt (g : E → ℝ) : (∫ u, g u ∂S y) =
      (∫ u, Real.exp (-W u))⁻¹ * (∫ u, Real.exp (-W u)*g u) := by
    rw [hSy, integral_tilted]
    rw [← integral_const_mul]
    apply integral_congr_ae
    filter_upwards [] with u
    change (Real.exp (-W u) / (∫ z, Real.exp (-W z))) • g u =
      (∫ z, Real.exp (-W z))⁻¹ * (Real.exp (-W u) * g u)
    simp only [smul_eq_mul, div_eq_mul_inv]
    ring
  refine ⟨hI _ hL,hI _ hG,hI _ hHess,hI _ hC,?_,?_⟩
  · rw [htilt,htilt,htilt,hidentity,mul_add]
  · rw [htilt,htilt]
    calc
      _ = (∫ u, Real.exp (-W u))⁻¹ *
          ((((α:ℝ)+1/η)/4) * (∫ u, Real.exp (-W u)*‖gradient f u‖^2)) := by ring
      _ ≤ _ := mul_le_mul_of_nonneg_left (hbound _ hcurv) (inv_nonneg.mpr hZ.le)

end AutoSamplingTheory.ExampleCases.ProximalBPS.ConditionalBochner

Exact module and namespace context

Scope and omitted-condition boundaries

  • Compact-test Bochner identity and curvature-energy bound only. No curvature-to-Poincare theorem, closed weighted operator/core, dense range or resolvent construction, noncompact score extension, variance estimate, macro coercivity, process/mixing/error/cost or complete-paper result.

Source and reuse

ASTIS parents called

Mathlib API called (external library)

  • MeasureTheory.tilted_of_not_integrable
  • MeasureTheory.integral_exp_pos
  • MeasureTheory.integrable_tilted_iff
  • MeasureTheory.integral_tilted

Mathematical sources

ASTIS prose is not a quotation or a source-equivalence certificate. Definitions and aliases are explained as constructions, not counted as new mathematical proofs.