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arXiv · 2305.15133

Rainbow Free Colorings and Rainbow Numbers for $x-y=z^2$

Katie Ansaldi·Gabriel Cowley·Eric Green·Kihyun Kim·JT Rapp
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Abstract

An exact r-coloring of a set $S$ is a surjective function $c:S \rightarrow \{1, 2, \ldots,r\}$. A rainbow solution to an equation over $S$ is a solution such that all components are a different color. We prove that every 3-coloring of $\mathbb{N}$ with an upper density greater than $(4^s-1)/(3 \cdot 4^s)$ contains a rainbow solution to $x-y=z^k$. The rainbow number for an equation in the set $S$ is the smallest integer $r$ such that every exact $r$-coloring has a rainbow solution. We compute the rainbow numbers of $\mathbb{Z}_p$ for the equation $x-y=z^k$, where $p$ is prime and $k\geq 2$.

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Katie Ansaldi, Gabriel Cowley, Eric Green, Kihyun Kim, JT Rapp. 2023-05-24. Rainbow Free Colorings and Rainbow Numbers for $x-y=z^2$. https://arxiv.org/abs/2305.15133

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