OAI/GroupTheory/PolycyclicRecognition/Geometry/CartanWeights.lean

GitHub source file

9 declarations, 0 contain sorry, 0 declared as axioms

Cartan roots descend to and separate canonical height

The roots vanish on the canonical nilpotent kernel. Conversely, vanishing of all nonzero roots forces zero canonical height. Thus the weight coordinates used by the box estimates are coordinates on the actual canonical quotient.

  1. theorem OAI.PolycyclicRecognition.cartan_weight_zero_of_height_zero line 27
  2. theorem OAI.PolycyclicRecognition.cartan_ad_nilpotent_of_weights_zero line 33
  3. def OAI.PolycyclicRecognition.cartanHeightSection line 50

    Source documentation

    Choose a linear Cartan representative of each height.

    def cartanHeightSection : HeightSpace T.character →ₗ[ℝ] H :=
    …

    Mentions: OAI.PolycyclicRecognition.HeightSpace

  4. theorem OAI.PolycyclicRecognition.cartanHeightSection_height line 54
  5. def OAI.PolycyclicRecognition.cartanHeightWeight line 61

    Source documentation

    A Cartan root as a linear form on the canonical height quotient.

    def cartanHeightWeight (χ : Weight ℝ H L) : HeightSpace T.character →ₗ[ℝ] ℝ :=
    …

    Mentions: OAI.PolycyclicRecognition.HeightSpace

  6. theorem OAI.PolycyclicRecognition.cartanHeightWeight_projection line 64
  7. theorem OAI.PolycyclicRecognition.cartanHeightWeights_separate line 77

    Source documentation

    The finite family of nonzero Cartan roots separates canonical height.

    theorem cartanHeightWeights_separate (w : HeightSpace T.character)
        (hw : ∀ χ : Weight ℝ H L, χ.IsNonZero → cartanHeightWeight T H χ w = 0) : w = 0 := by
    …

    Mentions: OAI.PolycyclicRecognition.HeightSpace, OAI.PolycyclicRecognition.cartanHeightWeight

  8. theorem OAI.PolycyclicRecognition.trace_ad_eq_sum_cartan_roots line 93

    Source documentation

    The trace of the adjoint action is the dimension-weighted sum of the actual Cartan roots, including their nonsemisimple parts.

    theorem trace_ad_eq_sum_cartan_roots (T : TriangularAdjoint L n) (h : H) :
        LinearMap.trace ℝ L (LieAlgebra.ad ℝ L h) =
          ∑ χ : Weight ℝ H L, Module.finrank ℝ (rootSpace H χ) • χ h := by
    …

    Mentions: OAI.PolycyclicRecognition.TriangularAdjoint

  9. theorem OAI.PolycyclicRecognition.balanced_cartanHeightWeights line 109

    Source documentation

    Unimodularity supplies the balancing relation on the canonical quotient.

    theorem balanced_cartanHeightWeights
        (hunimod : ∀ x : L, LinearMap.trace ℝ L (LieAlgebra.ad ℝ L x) = 0)
        (w : HeightSpace T.character) :
        ∑ χ : Weight ℝ H L,
          (Module.finrank ℝ (rootSpace H χ) : ℝ) * cartanHeightWeight T H χ w = 0 := by
    …

    Mentions: OAI.PolycyclicRecognition.HeightSpace, OAI.PolycyclicRecognition.cartanHeightWeight