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Main Authors: Cordero-Michel, Narda, Olsen, Mika
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2510.04990
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author Cordero-Michel, Narda
Olsen, Mika
author_facet Cordero-Michel, Narda
Olsen, Mika
contents Given a digraph $D$ with no loops, the \textit{dicoloring graph} of $D$, denoted by $\mathcal{D}_k(D)$, is the graph whose vertices are the acyclic $k$-colorings of $D$ and two colorings are adjacent in $\mathcal{D}_k(D)$ if they differ in color on exactly one vertex. In this paper, we prove that there is no expression $ϕ(\vecχ)$ in terms of the dichromatic number $\vecχ$, such that the graph $\mathcal{D}_k(D)$ is connected for all graphs $D$ and integers $k\geq ϕ(\vecχ)$. We give conditions for the dicoloring graph of two infinite families of circulant tournaments to be connected, and we provide upper bounds for its diameter. In particular, for the Payley tournament $\vec{C}_{7}(1,2,4)$, also known as $ST_7$, we prove that $\mathcal{D}_k(\vec{C}_{7}(1,2,4))$ is connected and has diameter 8, for each $k\geq 3$.
format Preprint
id arxiv_https___arxiv_org_abs_2510_04990
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Redicoloring some classes of circulant tournaments
Cordero-Michel, Narda
Olsen, Mika
Combinatorics
05C15, 05C20
Given a digraph $D$ with no loops, the \textit{dicoloring graph} of $D$, denoted by $\mathcal{D}_k(D)$, is the graph whose vertices are the acyclic $k$-colorings of $D$ and two colorings are adjacent in $\mathcal{D}_k(D)$ if they differ in color on exactly one vertex. In this paper, we prove that there is no expression $ϕ(\vecχ)$ in terms of the dichromatic number $\vecχ$, such that the graph $\mathcal{D}_k(D)$ is connected for all graphs $D$ and integers $k\geq ϕ(\vecχ)$. We give conditions for the dicoloring graph of two infinite families of circulant tournaments to be connected, and we provide upper bounds for its diameter. In particular, for the Payley tournament $\vec{C}_{7}(1,2,4)$, also known as $ST_7$, we prove that $\mathcal{D}_k(\vec{C}_{7}(1,2,4))$ is connected and has diameter 8, for each $k\geq 3$.
title Redicoloring some classes of circulant tournaments
topic Combinatorics
05C15, 05C20
url https://arxiv.org/abs/2510.04990