OAI/Geometry/HyperbolicGroups/PicturePlanarSeparator.lean

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2 declarations, 0 contain sorry, 0 declared as axioms

  1. theorem OAI.HyperbolicObstruction.PictureSwitch.PictureMap.planar_component_separator line 23

    Source documentation

    Literal genus-zero planar separator, independent of face degrees, vertex degrees, all parallel copies, and the specified vertex carrier.

    theorem planar_component_separator (hG : M.GenusZero) (hc : M.underlyingGraph.Connected)
        (U : Finset M.GraphVertex) :
        ∃ S : Finset M.GraphVertex, S ⊆ U ∧ S.card ≤ 11*Nat.sqrt U.card ∧
          ∀ W : Finset M.GraphVertex, W ⊆ U → Disjoint W S →
            (M.underlyingGraph.induce (W : Set M.GraphVertex)).Preconnected →
            2*W.card ≤ U.card := by
    …
  2. theorem OAI.HyperbolicObstruction.PictureSwitch.PictureMap.planar_balanced_separators line 35

    Source documentation

    A connected genus-zero rotation system has balanced separators.

    theorem planar_balanced_separators (hG : M.GenusZero) (hc : M.underlyingGraph.Connected) :
        HasBalancedSeparators M.underlyingGraph 11 :=
    …