Schur's theorem in integer lattices

TL;DR

This paper extends Schur's theorem to higher-dimensional integer lattices, establishing conditions for monochromatic solutions to linear equations in multi-colorings and providing computational examples for specific cases.

Contribution

It generalizes Schur's theorem to d-dimensional lattices with linear independence constraints, connecting to higher Ramsey numbers and offering computational insights.

Findings

Monochromatic solutions exist in higher dimensions when k ≥ d+1.

Established bounds involving higher-dimensional Ramsey numbers.

Provided computational examples for 2D case with 2-4 colors.

Abstract

A standard proof of Schur's Theorem yields that any $r$-coloring of $\{1,2,\dots,R_r-1\}$ yields a monochromatic solution to $x+y=z$, where $R_r$ is the classical $r$-color Ramsey number, the minimum $N$ such that any $r$-coloring of a complete graph on $N$ vertices yields a monochromatic triangle. We explore generalizations and modifications of this result in higher dimensional integer lattices, showing in particular that if $k\geq d+1$, then any $r$-coloring of $\{1,2,\dots,R_r(k)^d-1\}^d$ yields a monochromatic solution to $x_1+\cdots+x_{k-1}=x_k$ with $\{x_1,\dots,x_d\}$ linearly independent, where $R_r(k)$ is the analogous Ramsey number in which triangles are replaced by complete graphs on $k$ vertices. We also obtain computational results and examples in the case $d=2$, $k=3$, and $r\in\{2,3,4\}$.