Written on the Wall II - Conjecture 141 #
Reference: E. DeLaVina, Written on the Wall II, Conjectures of Graffiti.pc
theorem
WrittenOnTheWallII.GraphConjecture141.conjecture141
{α : Type u_1}
[Fintype α]
[DecidableEq α]
[Nontrivial α]
(G : SimpleGraph α)
(h : G.Connected)
:
WOWII Conjecture 141
For a simple connected graph G,
tree(G) ≥ ⌊girth(G) / 2⌋ - 1 + max_v l(v)
where tree(G) is the number of vertices of a largest induced tree subgraph,
girth(G) is the length of the shortest cycle (0 if acyclic), and
l(v) = indepNeighbors G v is the independence number of the neighbourhood of v.