Written on the Wall II - Conjecture 18 #
Reference: E. DeLaVina, Written on the Wall II, Conjectures of Graffiti.pc
theorem
WrittenOnTheWallII.GraphConjecture18.conjecture18
{α : Type u_1}
[Fintype α]
[DecidableEq α]
[Nontrivial α]
(G : SimpleGraph α)
[DecidableRel G.Adj]
(h : G.Connected)
:
WOWII Conjecture 18
For a simple connected graph $G$, the size $b(G)$ of a largest induced bipartite
subgraph satisfies $b(G) \ge \alpha(G) + \lceil \sqrt{\mathrm{eccSet}(G, M)} \rceil$,
where $\alpha(G)$ is the independence number, $M$ is the set of maximum-degree
vertices, and $\mathrm{eccSet}(G, M)$ is the set eccentricity of $M$ — the maximum
over all vertices of the minimum distance from that vertex to $M$. We use the
SimpleGraph.eccSet invariant.