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FormalConjectures.WrittenOnTheWallII.GraphConjecture18

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) :
have M := {v : α | G.degree v = G.maxDegree}; G.indepNum + (G.eccSet M) G.b

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.