OAI/GroupTheory/PolycyclicRecognition/Algebra/ConePolarTemplate.lean

GitHub source file

11 declarations, 0 contain sorry, 0 declared as axioms

Polar templates and their exact vanishing directions

The compact unit slice of the negative polar has support zero on the cone and strictly positive support at every functional outside the cone. These are the widths used in the cone-ideal covering argument.

  1. def OAI.PolycyclicRecognition.conePolarTemplate line 25

    Source documentation

    The unit-ball slice of the negative polar of the closed weight cone.

    def conePolarTemplate (C : ProperCone ℝ (StrongDual ℝ W)) : Set W :=
    …
  2. theorem OAI.PolycyclicRecognition.zero_mem_conePolarTemplate line 29
  3. theorem OAI.PolycyclicRecognition.isCompact_conePolarTemplate line 33
  4. theorem OAI.PolycyclicRecognition.convex_conePolarTemplate line 44
  5. theorem OAI.PolycyclicRecognition.exists_pos_on_conePolarTemplate line 60

    Source documentation

    Separation and rescaling supply a point with strictly positive evaluation.

    theorem exists_pos_on_conePolarTemplate (C : ProperCone ℝ (StrongDual ℝ W))
        {β : StrongDual ℝ W} (hβ : β ∉ C) :
        ∃ x ∈ conePolarTemplate C, 0 < β x := by
    …

    Mentions: OAI.PolycyclicRecognition.conePolarTemplate

  6. def OAI.PolycyclicRecognition.conePolarWidth line 79
  7. theorem OAI.PolycyclicRecognition.conePolarWidth_nonneg line 82
  8. theorem OAI.PolycyclicRecognition.conePolarWidth_eq_zero line 87
  9. theorem OAI.PolycyclicRecognition.conePolarWidth_pos line 97
  10. theorem OAI.PolycyclicRecognition.conePolarWidth_eq_zero_iff line 103
  11. theorem OAI.PolycyclicRecognition.conePolarWidth_smul line 110

    Source documentation

    Dilating the polar template multiplies every supporting width by the same scalar, so a maximizing word basis works for every positive radius.

    theorem conePolarWidth_smul (C : ProperCone ℝ (StrongDual ℝ W))
        (β : StrongDual ℝ W) {a : ℝ} (ha : 0 ≤ a) :
        sSup (β '' ((fun x : W => a • x) '' conePolarTemplate C)) =
          a * conePolarWidth C β := by
    …

    Mentions: OAI.PolycyclicRecognition.conePolarTemplate, OAI.PolycyclicRecognition.conePolarWidth