OAI/GroupTheory/PolycyclicRecognition/Geometry/CenteredHeightError.lean

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3 declarations, 0 contain sorry, 0 declared as axioms

Sublinear height errors after changing the basepoint

  1. theorem OAI.PolycyclicRecognition.centered_height_sublinear line 15

    Source documentation

    The same linear coefficient works after centering the coarse map at any fixed source point. Only the additive sublinear-error constant changes.

    theorem centered_height_sublinear
        (π : G →* Multiplicative W) (A : W →L[ℝ] W) (f : G → G)
        (hsub : ∀ ε : ℝ, 0 < ε → ∃ B : ℝ, 0 ≤ B ∧ ∀ g,
          ‖(π (f g)).toAdd - A ((π g).toAdd)‖ ≤ ε * dist 1 g + B)
        (x : G) :
        ∀ ε : ℝ, 0 < ε → ∃ B : ℝ, 0 ≤ B ∧ ∀ g,
          ‖(π ((f x)⁻¹ * f (x * g))).toAdd - A ((π g).toAdd)‖ ≤ ε * dist 1 g + B := by
    …
  2. theorem OAI.PolycyclicRecognition.centered_coarse_lipschitz line 44

    Source documentation

    Centering also preserves the coarse Lipschitz constants exactly.

    theorem centered_coarse_lipschitz (f : G → G) {L C : ℝ}
        (hf : ∀ a b, dist (f a) (f b) ≤ L * dist a b + C) (x a b : G) :
        dist ((f x)⁻¹ * f (x * a)) ((f x)⁻¹ * f (x * b)) ≤ L * dist a b + C := by
    …
  3. theorem OAI.PolycyclicRecognition.absolute_height_sublinear_of_centered_uniform line 53

    Source documentation

    Uniform centered height control supplies the absolute sublinear estimate used in representative independence.

    theorem absolute_height_sublinear_of_centered_uniform
        (π : G →* Multiplicative W) (A : W →L[ℝ] W) (f : G → G)
        (hsub : ∀ ε : ℝ, 0 < ε → ∃ B : ℝ, 0 ≤ B ∧ ∀ x g,
          ‖(π ((f x)⁻¹ * f (x * g))).toAdd - A ((π g).toAdd)‖ ≤ ε * dist 1 g + B) :
        ∀ ε : ℝ, 0 < ε → ∃ B : ℝ, 0 ≤ B ∧ ∀ g,
          ‖(π (f g)).toAdd - A ((π g).toAdd)‖ ≤ ε * dist 1 g + B := by
    …