English

Monochromatic sums and products in $\mathbb{N}$

Combinatorics 2016-05-06 v1 Dynamical Systems

Abstract

An old question in Ramsey theory asks whether any finite coloring of the natural numbers admits a monochromatic pair {x+y,xy}\{x+y,xy\}. We answer this question affirmatively in a strong sense by exhibiting a large new class of non-linear patterns which can be found in a single cell of any finite partition of N\mathbb{N}. Our proof involves a correspondence principle which transfers the problem into the language of topological dynamics. As a corollary of our main theorem we obtain partition regularity for new types of equations, such as x2y2=zx^2-y^2=z and x2+2y23z2=wx^2+2y^2-3z^2=w.

Keywords

Cite

@article{arxiv.1605.01469,
  title  = {Monochromatic sums and products in $\mathbb{N}$},
  author = {Joel Moreira},
  journal= {arXiv preprint arXiv:1605.01469},
  year   = {2016}
}

Comments

17 pages, 1 figure

R2 v1 2026-06-22T13:53:38.857Z