OAI/Geometry/HyperbolicGroups/PictureCotreeTree.lean
2 declarations, 0 contain sorry, 0 declared as axioms
- lemma
OAI.HyperbolicObstruction.PictureSwitch.PictureMap.complement_boundary_eqline 22 - theorem
OAI.HyperbolicObstruction.PictureSwitch.PictureMap.cotree_isTreeline 37Source documentation
The complement of ANY literal spanning-tree subpairing is a dual tree, not just the particular Kruskal forest supplied by tree_cotree. This is needed when the primal tree is chosen for a radius bound.
theorem cotree_isTree (hG : M.GenusZero) (hspan : SameCycle.setoid M.vertex ⊔ SameCycle.setoid q = ⊤) (hboundary : cycles (M.vertex*q) = 1) : (M.cotreeGraph q hq).IsTree := by …