OAI/Topology/ArtinGroups/ParabolicIntersections/TreeTripod.lean
5 declarations, 0 contain sorry, 0 declared as axioms
Common prefixes and tripods for paths in a tree.
- lemma
OAI.HarmonicArtin.ParabolicIntersections.TreeAction.walk_common_prefixline 11 - lemma
OAI.HarmonicArtin.ParabolicIntersections.TreeAction.tree_tripodline 32 - lemma
OAI.HarmonicArtin.ParabolicIntersections.TreeAction.prefixes_comparableline 56 - lemma
OAI.HarmonicArtin.ParabolicIntersections.TreeAction.common_support_in_prefixline 70 - lemma
OAI.HarmonicArtin.ParabolicIntersections.TreeAction.tree_branchpointline 87Source documentation
The common prefix contains every common vertex of the two paths.
lemma tree_branchpoint (hT : T.IsAcyclic) {x y z : V} (p : T.Walk x y) (q : T.Walk x z) (r : T.Walk y z) (hp : p.IsPath) (hq : q.IsPath) (hr : r.IsPath) : ∃ b, ∃ hbp : b∈p.support, b∈q.support ∧ b∈r.support ∧ ∀ w∈p.support,w∈q.support → w∈(p.takeUntil b hbp).support := by …