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Erdős problem 22

Let ϵ>0\epsilon > 0 and let nn be sufficiently large depending on ϵ\epsilon. Is there a graph on nn vertices with at least n2/8n^2/8 many edges which contains no K4K_4, such that the largest independent set has size at most ϵn\epsilon n?

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FormalConjectures/ErdosProblems/

22.lean

Retained formal statement4 of 5

The matching upper bound, due to Szemerédi [Sz72]: a K4K_4-free graph on nn vertices whose independence number is sublinear in nn has at most (1/8+o(1))n2(1/8 + o(1))n^2 edges. That is, for every ϵ>0\epsilon > 0 there is a δ>0\delta > 0 such that for all sufficiently large nn, every K4K_4-free graph GG on nn vertices with α(G)δn\alpha(G) \leq \delta n has at most (1/8+ϵ)n2(1/8 + \epsilon)n^2 edges.

FormalConjectures/ErdosProblems/22.leanErdos22.erdos_22.variants.szemeredi_upper6 linesExact file
∀ (ε : ℝ),  0 < ε →    ∃ δ,      0 < δ ∧        ∀ᶠ (n : ℕ) in Filter.atTop,          ∀ (G : SimpleGraph (Fin n)), G.CliqueFree 4 → ↑G.indepNum ≤ δ * ↑n → ↑G.edgeFinset.card ≤ (1 / 8 + ε) * ↑n ^ 2
SolvedStatement only, no proof

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