OAI/GroupTheory/PolycyclicRecognition/Algebra/FiniteDynkinDifference.lean

GitHub source file

2 declarations, 0 contain sorry, 0 declared as axioms

Difference bounds for the actual finite Dynkin polynomial

The middle input in a conjugation product vanishes at time zero. These bounds retain that factor rather than losing it in an absolute polynomial estimate; this gives polynomial coarse speed for Cartan-fiber paths.

  1. theorem OAI.PolycyclicRecognition.norm_basis_evalBracketWord_sub_le line 23

    Source documentation

    A bracket word is Lipschitz on a coordinate ball, with one fewer power of its radius than the absolute word bound.

    theorem norm_basis_evalBracketWord_sub_le
        (X Y : I → L) {C M D : ℝ} (hC : 0 ≤ C) (hM : 0 ≤ M) (hD : 0 ≤ D)
        (hbracket : ∀ i j k, |b.repr ⁅b i, b j⁆ k| ≤ C)
        (hX : ∀ i, ‖b.equivFun (X i)‖ ≤ M) (hY : ∀ i, ‖b.equivFun (Y i)‖ ≤ M)
        (hXY : ∀ i, ‖b.equivFun (X i - Y i)‖ ≤ D) (w : FreeMagma I) :
        ‖b.equivFun (evalBracketWord X w - evalBracketWord Y w)‖ ≤
          (bracketWordLength w : ℝ) * ((Fintype.card J : ℝ) ^ 2 * C) ^ bracketWordNodes w *
            M ^ bracketWordNodes w * D := by
    …

    Mentions: OAI.PolycyclicRecognition.evalBracketWord, OAI.PolycyclicRecognition.bracketWordLength, OAI.PolycyclicRecognition.bracketWordNodes

  2. theorem OAI.PolycyclicRecognition.exists_finiteDynkinPolynomial_difference_bound line 69

    Source documentation

    Fixed finite Dynkin coefficients give a uniform polynomial Lipschitz bound on coordinate balls. No extra group-law or analytic input is used.

    theorem exists_finiteDynkinPolynomial_difference_bound
        {c n : ℕ} (a : DynkinCoefficients c n) {C : ℝ} (hC : 0 ≤ C)
        (hbracket : ∀ i j k, |b.repr ⁅b i, b j⁆ k| ≤ C) :
        ∃ A : ℝ, 0 ≤ A ∧ ∀ (X Y : Fin n → L) (M D : ℝ), 0 ≤ M → 0 ≤ D →
          (∀ i, ‖b.equivFun (X i)‖ ≤ M) → (∀ i, ‖b.equivFun (Y i)‖ ≤ M) →
          (∀ i, ‖b.equivFun (X i - Y i)‖ ≤ D) →
          ‖b.equivFun (finiteDynkinPolynomial a X - finiteDynkinPolynomial a Y)‖ ≤
            A * (1 + M) ^ c * D := by
    …

    Mentions: OAI.PolycyclicRecognition.DynkinCoefficients, OAI.PolycyclicRecognition.finiteDynkinPolynomial