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Erdős problem 579

Let δ>0\delta > 0. If nn is sufficiently large and GG is a graph on nn vertices with no K2,2,2K_{2,2,2} (the octahedron) and at least δn2\delta n^2 edges, must GG contain an independent set of size δn\gg_\delta n?

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FormalConjectures/ErdosProblems/

579.lean

Retained formal statement2 of 3

The partial result of Erdős, Hajnal, Sós, and Szemerédi [EHSS83]: the statement of erdos_579 holds whenever the edge-density coefficient exceeds 1/81/8. That is, for every δ>1/8\delta > 1/8 there is a c>0c > 0 such that for all sufficiently large nn, every K2,2,2K_{2,2,2}-free graph GG on nn vertices with at least δn2\delta n^2 edges has an independent set of size at least cnc n.

FormalConjectures/ErdosProblems/579.leanErdos579.erdos_579.variants.ehss_large_delta7 linesExact file
∀ (δ : ℝ),  1 / 8 < δ →c,      0 < c        ∀ᶠ (n : ℕ) in Filter.atTop,          ∀ (G : SimpleGraph (Fin n)),            Erdos579.octahedron.Free G → δ * ↑n ^ 2 ≤ ↑G.edgeFinset.cardc * ↑n ≤ ↑G.indepNum
SolvedStatement only, no proof

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