OAI/Topology/ArtinGroups/ParabolicIntersections/TreeBranch.lean
4 declarations, 0 contain sorry, 0 declared as axioms
Reflecting a segment at an endpoint and extending it along a new edge.
- lemma
OAI.HarmonicArtin.ParabolicIntersections.TreeAction.moved_first_vertex_ne_endpointline 12 - theorem
OAI.HarmonicArtin.ParabolicIntersections.TreeAction.reflected_pairline 19Source 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
- lemma
OAI.HarmonicArtin.ParabolicIntersections.TreeAction.reverse_concat_isPathline 50Source 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 … - theorem
OAI.HarmonicArtin.ParabolicIntersections.TreeAction.extended_pairline 58Source 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