OAI/Topology/ArtinGroups/ParabolicIntersections/TreeBranch.lean

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4 declarations, 0 contain sorry, 0 declared as axioms

Reflecting a segment at an endpoint and extending it along a new edge.

  1. lemma OAI.HarmonicArtin.ParabolicIntersections.TreeAction.moved_first_vertex_ne_endpoint line 12
  2. theorem OAI.HarmonicArtin.ParabolicIntersections.TreeAction.reflected_pair line 19

    Source documentation

    Reflecting a path across its initial vertex intersects its endpoint stabilizer with a conjugate, and still gives an endpoint stabilizer.

    theorem reflected_pair (u v : V) (p : T.Walk v u) (hp : p.IsPath)
        (g : G) (hg : g • v=v) (hw : g • p.snd≠p.snd) :
        pairStabilizer (G := G) u (g • u)=pairStabilizer (G := G) u v ⊓
    …

    Mentions: OAI.HarmonicArtin.ParabolicIntersections.TreeAction.pairStabilizer

  3. lemma OAI.HarmonicArtin.ParabolicIntersections.TreeAction.reverse_concat_isPath line 50

    Source documentation

    An edge leaving the initial direction of a path extends the path.

    lemma reverse_concat_isPath {u v w : V} (p : T.Walk v u) (hp : p.IsPath)
        (hadj : T.Adj v w) (hw : w≠p.snd) : (p.reverse.concat hadj).IsPath := by
    …
  4. theorem OAI.HarmonicArtin.ParabolicIntersections.TreeAction.extended_pair line 58

    Source documentation

    If the old stabilizer fixes the added vertex, extension preserves it.

    theorem extended_pair (u v w : V) (p : T.Walk v u) (hp : p.IsPath)
        (hadj : T.Adj v w) (hw : w≠p.snd)
        (hfix : pairStabilizer (G := G) u v≤MulAction.stabilizer G w) :
    …

    Mentions: OAI.HarmonicArtin.ParabolicIntersections.TreeAction.pairStabilizer