English

Monochromatic products in random integer sets

Combinatorics 2026-01-15 v2 Number Theory

Abstract

A well-known consequence of Schur's theorem is that for rNr\in \mathbb{N}, if nn is sufficiently large, then any rr-colouring of [n][n] results in monochromatic a,b,c[n]a,b,c\in [n] such that ab=cab=c. In this paper we are interested in the threshold at which the binomial random set [n]p[n]_p almost surely inherits this Ramsey-type property. In particular for r=2r=2 colours, we show that this threshold lies between n1/9o(1)n^{-1/9-o(1)} and n1/11n^{-1/11}. Whilst analogous questions for solutions to (sets of) linear equations are now well understood, our work suggests that both the behaviour of the thresholds and the proof methods needed to determine them differ substantially in the non-linear setting.

Keywords

Cite

@article{arxiv.2512.04916,
  title  = {Monochromatic products in random integer sets},
  author = {Roger Lidón and Darío Martínez and Patrick Morris and Miquel Ortega},
  journal= {arXiv preprint arXiv:2512.04916},
  year   = {2026}
}

Comments

15 pages, 1 figure. Some typos fixed

R2 v1 2026-07-01T08:09:44.539Z