OAI/GroupTheory/PolycyclicRecognition/Geometry/BoundaryRaySeparation.lean
3 declarations, 0 contain sorry, 0 declared as axioms
Uniform separation after deleting a whole positive weight ray
The original generator list may contain repeated positive rays. A positive balanced relation still makes the remaining rays separate the height space.
- theorem
OAI.PolycyclicRecognition.nonpos_of_vanishing_outside_positive_rayline 21Source documentation
A balanced positive family cannot be positive on its only nonzero ray.
theorem nonpos_of_vanishing_outside_positive_ray (α : I → W →ₗ[ℝ] ℝ) (c : I → ℝ) (hc : ∀ i, 0 < c i) (hrel : ∀ w, ∑ i, c i * α i w = 0) (k : I) (w : W) (hw : ∀ i, α i ∉ positiveWeightRay (α k) → α i w = 0) : α k w ≤ 0 := by … - theorem
OAI.PolycyclicRecognition.separates_outside_positive_rayline 40Source documentation
Removing every duplicate of one positive ray preserves separation.
theorem separates_outside_positive_ray (α : I → W →ₗ[ℝ] ℝ) (c : I → ℝ) (hc : ∀ i, 0 < c i) (hrel : ∀ w, ∑ i, c i * α i w = 0) (hsep : ∀ w, (∀ i, α i w = 0) → w = 0) (k : I) (w : W) (hw : ∀ i, α i ∉ positiveWeightRay (α k) → α i w = 0) : w = 0 := by … - theorem
OAI.PolycyclicRecognition.exists_bound_outside_positive_rayline 61Source documentation
The norm bound is uniform over the finite generator list, including when several generators determine the same positive ray.
theorem exists_bound_outside_positive_ray [FiniteDimensional ℝ W] (α : I → W →ₗ[ℝ] ℝ) (c : I → ℝ) (hc : ∀ i, 0 < c i) (hrel : ∀ w, ∑ i, c i * α i w = 0) (hsep : ∀ w, (∀ i, α i w = 0) → w = 0) : ∃ C : ℝ, 0 < C ∧ ∀ (k : I) (w : W) (B : ℝ), 0 ≤ B → (∀ i, α i ∉ positiveWeightRay (α k) → |α i w| ≤ B) → ‖w‖ ≤ C * B := by …