English

Phase transitions of the Erd\H{o}s-Gy\'{a}rf\'{a}s function

Combinatorics 2025-04-09 v1

Abstract

Given positive integers p,qp,q. For any integer k2k\ge2, an edge coloring of the complete kk-graph Kn(k)K_n^{(k)} is said to be a (p,q)(p,q)-coloring if every copy of Kp(k)K_p^{(k)} receives at least qq colors. The Erd\H{o}s-Gy\'{a}rf\'{a}s function fk(n,p,q)f_k(n,p,q) is the minimum number of colors that are needed for Kn(k)K_n^{(k)} to have a (p,q)(p,q)-coloring. Conlon, Fox, Lee and Sudakov (\emph{IMRN, 2015}) conjectured that for any positive integers p,kp, k and ii with k3k\ge3 and 1i<k1\le i<k, fk(n,p,(piki))=(log(i1)n)o(1)f_k(n,p,{{p-i}\choose{k-i}})=(\log_{(i-1)}n)^{o(1)}, where log(i)n\log_{(i)}n is an iterated ii-fold logarithm in nn. It has been verified to be true for k=3,p=4,i=1k=3, p=4, i=1 by Conlon et. al (\emph{IMRN, 2015}), for k=3,p=5,i=2k=3, p=5, i=2 by Mubayi (\emph{JGT, 2016}), and for all k4,p=k+1,i=1k\ge 4, p=k+1,i=1 by B. Janzer and O. Janzer (\emph{JCTB, 2024}). In this paper, we give new constructions and show that this conjecture holds for infinitely many new cases, i.e., it holds for all k4k\ge4, p=k+2p=k+2 and i=k1i=k-1.

Keywords

Cite

@article{arxiv.2504.05647,
  title  = {Phase transitions of the Erd\H{o}s-Gy\'{a}rf\'{a}s function},
  author = {Xinyu Hu and Qizhong Lin and Xin Lu and Guanghui Wang},
  journal= {arXiv preprint arXiv:2504.05647},
  year   = {2025}
}

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11 pages