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Erdős problem 615

Does there exist some constant c>0c > 0 such that for all sufficiently large nn, if GG is a graph with nn vertices and at least (1/8c)n2(1/8 - c)n^2 edges then GG must contain either a K4K_4 or an independent set on at least n/lognn/\log n vertices?

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FormalConjectures/ErdosProblems/

615.lean

Retained formal statement3 of 4

The complementary result of Sudakov [Su03]: if f(n)/lognf(n)/\sqrt{\log n} \to \infty then rt(n;4,nef(n))=o(n2)\mathrm{rt}(n; 4, ne^{-f(n)}) = o(n^2); that is, for every ϵ>0\epsilon > 0 and all sufficiently large nn, every K4K_4-free graph on nn vertices with independence number at most nef(n)ne^{-f(n)} has at most ϵn2\epsilon n^2 edges.

FormalConjectures/ErdosProblems/615.leanErdos615.erdos_615.variants.sudakov7 linesExact file
∀ (f : ℕ → ℝ),  Filter.Tendsto (fun n => f n / √(Real.logn)) Filter.atTop Filter.atTop    ∀ (ε : ℝ),      0 < ε →        ∀ᶠ (n : ℕ) in Filter.atTop,          ∀ (G : SimpleGraph (Fin n)),            G.CliqueFree 4 → ↑G.indepNum ≤ ↑n * Real.exp (-f n) → ↑G.edgeFinset.card ≤ ε * ↑n ^ 2
SolvedStatement only, no proof

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