OAI/GroupTheory/PolycyclicRecognition/Geometry/CanonicalHeight.lean
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.
- def
OAI.PolycyclicRecognition.heightKernelline 23Source 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
- abbrev
OAI.PolycyclicRecognition.HeightSpaceline 26Source 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
- def
OAI.PolycyclicRecognition.heightProjectionline 29Source 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
- def
OAI.PolycyclicRecognition.heightCharacterline 33Source 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
- theorem
OAI.PolycyclicRecognition.heightCharacter_projectionline 36 - theorem
OAI.PolycyclicRecognition.heightProjection_surjectiveline 39 - theorem
OAI.PolycyclicRecognition.mem_heightKernelline 42 - theorem
OAI.PolycyclicRecognition.heightCharacters_separateline 48Source 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
- theorem
OAI.PolycyclicRecognition.heightCharacter_relationline 56Source 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
- theorem
OAI.PolycyclicRecognition.heightSpace_subsingleton_of_characters_zeroline 64Source 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
- theorem
OAI.PolycyclicRecognition.characters_zero_of_heightSpace_subsingletonline 75Source 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
- theorem
OAI.PolycyclicRecognition.heightProjection_lie_eq_zeroline 87Source 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 …