OAI/GroupTheory/PolycyclicRecognition/Geometry/CanonicalHeight.lean

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12 declarations, 0 contain sorry, 0 declared as axioms

The linear canonical height quotient

The height space is the quotient by the common kernel of the diagonal adjoint characters. The induced characters on this quotient separate points.

  1. def OAI.PolycyclicRecognition.heightKernel line 23

    Source documentation

    The common kernel of the diagonal characters. Empty families give ⊤.

    Also declared: ComparatorChallenges/PolycyclicRecognition.lean:142 (same declaration text).

    def heightKernel (χ : I → L →ₗ[ℝ] ℝ) : Submodule ℝ L := ⨅ i, (χ i).ker
  2. abbrev OAI.PolycyclicRecognition.HeightSpace line 26

    Source documentation

    The canonical linear height space.

    Also declared: ComparatorChallenges/PolycyclicRecognition.lean:145 (same declaration text).

    abbrev HeightSpace (χ : I → L →ₗ[ℝ] ℝ) := L ⧸ heightKernel χ

    Mentions: OAI.PolycyclicRecognition.heightKernel

  3. def OAI.PolycyclicRecognition.heightProjection line 29

    Source documentation

    The quotient map defining infinitesimal height.

    Also declared: ComparatorChallenges/PolycyclicRecognition.lean:148 (same declaration text).

    def heightProjection (χ : I → L →ₗ[ℝ] ℝ) : L →ₗ[ℝ] HeightSpace χ :=
    …

    Mentions: OAI.PolycyclicRecognition.HeightSpace

  4. def OAI.PolycyclicRecognition.heightCharacter line 33

    Source documentation

    Each character descends to the height quotient.

    def heightCharacter (χ : I → L →ₗ[ℝ] ℝ) (i : I) : HeightSpace χ →ₗ[ℝ] ℝ :=
    …

    Mentions: OAI.PolycyclicRecognition.HeightSpace

  5. theorem OAI.PolycyclicRecognition.heightCharacter_projection line 36
  6. theorem OAI.PolycyclicRecognition.heightProjection_surjective line 39
  7. theorem OAI.PolycyclicRecognition.mem_heightKernel line 42
  8. theorem OAI.PolycyclicRecognition.heightCharacters_separate line 48

    Source documentation

    The common kernel has been removed: all induced character values vanish only at the zero height.

    theorem heightCharacters_separate (χ : I → L →ₗ[ℝ] ℝ) (w : HeightSpace χ)
        (hw : ∀ i, heightCharacter χ i w = 0) : w = 0 := by
    …

    Mentions: OAI.PolycyclicRecognition.HeightSpace, OAI.PolycyclicRecognition.heightCharacter

  9. theorem OAI.PolycyclicRecognition.heightCharacter_relation line 56

    Source documentation

    A relation among the original characters descends without changing its coefficients. This is used with the trace-zero, positive-multiplicity relation.

    theorem heightCharacter_relation [Fintype I]
        (χ : I → L →ₗ[ℝ] ℝ) (c : I → ℝ)
        (h : ∀ x : L, ∑ i, c i * χ i x = 0) (w : HeightSpace χ) :
        ∑ i, c i * heightCharacter χ i w = 0 := by
    …

    Mentions: OAI.PolycyclicRecognition.HeightSpace, OAI.PolycyclicRecognition.heightCharacter

  10. theorem OAI.PolycyclicRecognition.heightSpace_subsingleton_of_characters_zero line 64

    Source documentation

    Vanishing diagonal characters give a zero-dimensional height quotient.

    theorem heightSpace_subsingleton_of_characters_zero
        (χ : I → L →ₗ[ℝ] ℝ) (hχ : ∀ i, χ i = 0) : Subsingleton (HeightSpace χ) := by
    …

    Mentions: OAI.PolycyclicRecognition.HeightSpace

  11. theorem OAI.PolycyclicRecognition.characters_zero_of_heightSpace_subsingleton line 75

    Source documentation

    Conversely, a trivial height quotient forces all the diagonal characters to vanish.

    theorem characters_zero_of_heightSpace_subsingleton
        (χ : I → L →ₗ[ℝ] ℝ) [Subsingleton (HeightSpace χ)] : ∀ i, χ i = 0 := by
    …

    Mentions: OAI.PolycyclicRecognition.HeightSpace

  12. theorem OAI.PolycyclicRecognition.heightProjection_lie_eq_zero line 87

    Source documentation

    Characters vanishing on brackets make every bracket have zero height.

    theorem heightProjection_lie_eq_zero
        (χ : I → L →ₗ[ℝ] ℝ) (hχ : ∀ i (x y : L), χ i ⁅x, y⁆ = 0) (x y : L) :
        heightProjection χ ⁅x, y⁆ = 0 := by
    …

    Mentions: OAI.PolycyclicRecognition.heightProjection