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JOURNALS // Proceedings of the Yerevan State University, series Physical and Mathematical Sciences // Archive

Proceedings of the YSU, Physical and Mathematical Sciences, 2025 Volume 59, Issue 1, Pages 1–9 (Mi uzeru1134)

Mathematics

On strong chromatic index of some operations on graphs

A. Ê. Drambyan

Russian-Armenian University, Yerevan

Abstract: A strong edge-coloring of a graph $G$ is a mapping $\phi : E(G) \rightarrow \mathbb{N}$ such that the edges at distance $0$ or $1$ receive distinct colors. The minimum number of colors required for such a coloring is called the strong chromatic index of $G$ and is denoted by $\chi_s'(G)$. In this paper, we investigate the strong chromatic index of the Mycielskian $\mu(G)$ of graphs $G$ and corona products $G \odot H$ of graphs $G$ and $H$. In particular, we give tight lower and upper bounds on $\chi_s'(G \odot H)$. Moreover, we provide specific structural criteria, under which the upper bound is sharp. We also derive tight lower and upper bounds on $\chi_s'(\mu(G))$ for Mycielskian of graphs.

Keywords: edge-coloring, strong edge-coloring, strong chromatic index, corona product, Mycielskian

MSC: Primary 05C15; Secondary 05C76

Received: 25.01.2025
Revised: 03.03.2025
Accepted: 17.03.2025

Language: English

DOI: 10.46991/PYSUA.2025.59.1.001



© Steklov Math. Inst. of RAS, 2026