Erdős Problem a Daythe open tracker

Erdős Problem #563

OPENdatabase updated 2025-08-31

No proof or disproof is known, and it isn't known whether a finite computation could settle it.

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A 2-coloring of \(K_n\) (represented by graph \(G\) on \(\mathrm{Fin}\; n\)) is balanced on subsets of size at least \(m\) with parameter \(\alpha\) if every \(X \subseteq [n]\) with \(|X| \geq m\) contains more than \(\alpha \binom{|X|}{2}\) edges of each color.

\(F(n,\alpha)\) is the smallest \(m\) such that there exists a 2-coloring of the edges of \(K_n\) so that every \(X\subseteq [n]\) with \(|X|\geq m\) contains more than \(\alpha\binom{|X|}{2}\) edges of each color.

Let \(F(n,\alpha)\) denote the smallest \(m\) such that there exists a \(2\)-colouring of the edges of \(K_n\) so that every \(X\subseteq [n]\) with \(\lvert X\rvert\geq m\) contains more than \(\alpha \binom{\lvert X\rvert}{2}\) many edges of each colour. Prove that, for every \(0\leq \alpha < 1/2\), \[F(n,\alpha)\sim c_\alpha\log n\] for some constant \(c_\alpha\) depending only on \(\alpha\). This problem is #39 in Ramsey Theory in the graphs problem collection.
Statement as formalized in Formal Conjectures (Google DeepMind, Apache-2.0) · their label: research open. The authoritative wording is on erdosproblems.com/563.
Prizenone
Topicsgraph theory, ramsey theory, hypergraphs
Statement in LeanFormal Conjectures
Solution in Leanno
Original pageerdosproblems.com/563
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Proved the exact piecewise formula R_alpha(4)=18,10,6, computed the complete n<=7 extremal table, and reduced the asymptotic question to existence of lim_k log R_alpha(k)/k, whose alpha=0 case is the

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