OAI/GroupTheory/PolycyclicRecognition/Geometry/CartanSupportLegs.lean

GitHub source file

4 declarations, 0 contain sorry, 0 declared as axioms

Support legs in the actual Cartan subgroup

The canonical height section gives a one-parameter subgroup realizing any height displacement. Its continuity follows from the published faithful exponential representation, and its height traces the exact affine segment.

  1. theorem OAI.PolycyclicRecognition.continuous_exp_line_of_published_realization line 31

    Source documentation

    Continuity of every actual exponential one-parameter subgroup.

    theorem continuous_exp_line_of_published_realization
        [SimplyConnectedSpace G]
        (realize : ExponentialLinearRealizationInput (EG := EG) (G := G))
    …

    Mentions: OAI.PolycyclicRecognition.ExponentialLinearRealizationInput

  2. def OAI.PolycyclicRecognition.supportLegDirection line 50

    Source documentation

    The actual Cartan direction of a height displacement.

    def supportLegDirection (w₀ w₁ : W) : H :=
    …
  3. theorem OAI.PolycyclicRecognition.supportLegDirection_height line 54
  4. theorem OAI.PolycyclicRecognition.exists_cartan_support_leg_bound line 61

    Source documentation

    An actual one-parameter leg visits the requested height segment with uniform coarse speed at every scale and on every translated sheet.

    theorem exists_cartan_support_leg_bound
        (π : G →* Multiplicative W)
        (hπ : ∀ x, (π (Exp x)).toAdd = eW (heightProjection T.character x))
        {E : Set W} (hE : Convex ℝ E) {w₀ w₁ : W} (hw₀ : w₀ ∈ E) (hw₁ : w₁ ∈ E) :
        ∃ C : ℝ, 0 ≤ C ∧ ∀ (x : G) (r : ℝ), 0 ≤ r → (π x).toAdd = r • w₀ →
          let d := fun t : ℝ => Exp (t • (supportLegDirection T H eW w₀ w₁ :
    …

    Mentions: OAI.PolycyclicRecognition.heightProjection, OAI.PolycyclicRecognition.supportLegDirection