Distinguishing chromatic number of the hierarchical product of graphs

Year 2026, Volume: 55 Issue: 2 , 546 - 554 , 29.04.2026

Tayyebeh Amouzegar , Kazem Khashyarmanesh

https://doi.org/10.15672/hujms.1215743

https://izlik.org/JA28CF47YA

Abstract

The  distinguishing chromatic number  $\chi_D(G)$ of a graph $G$ is the smallest number of colors needed to properly color the vertices of $G$ such that the only automorphism of $G$ that preserves colors is the identity. Studying the distinguishing chromatic number of graphs produced some interesting work, and in continuation, we may prefer toinvestigate the   distinguishing chromatic number  of the hierarchical product of  graphs.  The paper addresses the question   of Choi, Hartke, and Kaule as to whether there are  graphs for which the distinguishing chromatic number is near  the chromatic number.

Keywords

chromatic number , distinguishing chromatic number , graph automorphism , vertex coloring , hierarchical product of graphs

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