OAI/GroupTheory/PolycyclicRecognition/Algebra/InverseAverageL2.lean

GitHub source file

5 declarations, 0 contain sorry, 0 declared as axioms

The inverse transfer belongs to L²

The transfer in inverse coordinates is averaged over an actual positive compact Haar region. Local L² integrability and Jensen's estimate justify this construction for the finite inverse-section measure.

  1. theorem OAI.PolycyclicRecognition.inverseFiberTransfer_memLp_normalized line 29

    Source documentation

    The corrected inverse transfer is square integrable on a normalized compact fiber region.

    theorem inverseFiberTransfer_memLp_normalized
        (m : Measure G) [IsFiniteMeasureOnCompacts m]
        (μ ν : Measure (NormalizedPair G Λ)) [IsFiniteMeasure μ] [IsFiniteMeasure ν]
        (hprod : inversePairCoupling m μ = ν.prod m)
        (π l : G →* Multiplicative W)
        (hπ : Continuous fun g => (π g).toAdd) (hl : Continuous fun g => (l g).toAdd)
        {φ : NormalizedPair G Λ → W} (hφ : MemLp φ 2 μ)
        {B : Set G} (hB : IsCompact B) (hB0 : m B ≠ 0) :
        MemLp (inverseFiberTransfer π l φ) 2 (ν.prod (normalizedRestriction m B)) := by
    …

    Mentions: OAI.PolycyclicRecognition.NormalizedPair, OAI.PolycyclicRecognition.inversePairCoupling, OAI.PolycyclicRecognition.inverseFiberTransfer, OAI.PolycyclicRecognition.normalizedRestriction

  2. theorem OAI.PolycyclicRecognition.inverseFiberTransfer_shift_memLp line 46

    Source documentation

    Translating the compact fiber region by its evaluation center retains square integrability. Stationarity handles the normalized section shift.

    theorem inverseFiberTransfer_shift_memLp
        (ν : Measure (NormalizedPair G Λ)) [IsFiniteMeasure ν]
        [SMulInvariantMeasure G (NormalizedPair G Λ) ν]
        (β : Measure G) [IsProbabilityMeasure β]
        (π l : G →* Multiplicative W) (hl : Continuous fun g => (l g).toAdd)
        (φ : NormalizedPair G Λ → W)
        (hD : MemLp (inverseFiberTransfer π l φ) 2 (ν.prod β)) (y : G) :
        MemLp (fun q : NormalizedPair G Λ × G =>
          inverseFiberTransfer π l φ (q.1, q.1.val.1 y * q.2)) 2 (ν.prod β) := by
    …

    Mentions: OAI.PolycyclicRecognition.NormalizedPair, OAI.PolycyclicRecognition.inverseFiberTransfer

  3. theorem OAI.PolycyclicRecognition.inverseAveragedTransfer_memLp line 80

    Source documentation

    The averaged inverse transfer is an actual square-integrable function for the section measure constructed by Haar factorization.

    theorem inverseAveragedTransfer_memLp
        (m : Measure G) [IsFiniteMeasureOnCompacts m]
        (μ ν : Measure (NormalizedPair G Λ)) [IsFiniteMeasure μ] [IsFiniteMeasure ν]
        (hprod : inversePairCoupling m μ = ν.prod m)
        (π l : G →* Multiplicative W)
        (hπ : Continuous fun g => (π g).toAdd) (hl : Continuous fun g => (l g).toAdd)
        {φ : NormalizedPair G Λ → W} (hφ : MemLp φ 2 μ)
        {B : Set G} (hB : IsCompact B) (hB0 : m B ≠ 0) :
        MemLp (inverseAveragedTransfer (normalizedRestriction m B) π l φ) 2 ν := by
    …

    Mentions: OAI.PolycyclicRecognition.NormalizedPair, OAI.PolycyclicRecognition.inversePairCoupling, OAI.PolycyclicRecognition.inverseAveragedTransfer, OAI.PolycyclicRecognition.normalizedRestriction

  4. theorem OAI.PolycyclicRecognition.inverseAverageError_sq_le line 98

    Source documentation

    For two square-integrable fiber restrictions, the average error is bounded by their whole-product squared oscillation.

    theorem inverseAverageError_sq_le
        (β : Measure G) [IsProbabilityMeasure β]
        (π l : G →* Multiplicative W) (φ : NormalizedPair G Λ → W)
        (y : G) (p : NormalizedPair G Λ)
        (h₁ : MemLp (fun x => inverseFiberTransfer π l φ (p, p.val.1 y * x)) 2 β)
        (h₂ : MemLp (fun x => inverseFiberTransfer π l φ (p, x)) 2 β) :
        ‖inverseAverageError β π l φ y p‖ ^ 2 ≤
          ∫ x₁, ∫ x₂, ‖pairTransferDefect π l φ (x₂⁻¹ * (p.val.1 y * x₁))
            (pairChartTransition.symm (p, x₂)).2‖ ^ 2 ∂β ∂β := by
    …

    Mentions: OAI.PolycyclicRecognition.NormalizedPair, OAI.PolycyclicRecognition.inverseFiberTransfer, OAI.PolycyclicRecognition.inverseAverageError, OAI.PolycyclicRecognition.pairTransferDefect

  5. theorem OAI.PolycyclicRecognition.inverse_transfer_linear_coefficient line 116

    Source documentation

    Algebraic final step of the inverse transfer: the linear coefficient is precisely the inverse of the original coefficient.

    theorem inverse_transfer_linear_coefficient (A : W ≃L[ℝ] W)
        {v w ψ ψ' R : W} (h : ψ' - ψ = -v + A w + R) :
        w + (-A.symm ψ') - (-A.symm ψ) = A.symm v - A.symm R := by
    …