TWO RESULTS ON THE PALETTE INDEX OF GRAPHS
Open Access
- 21 May 2021
- journal article
- Published by Yerevan State University in Proceedings of the YSU A: Physical and Mathematical Sciences
- Vol. 55 (1 (254)), 36-43
- https://doi.org/10.46991/pysu:a/2021.55.1.036
Abstract
Given a proper edge coloring $\alpha$ of a graph $G$, we define the palette $S_G(v,\alpha)$ of a vertex $v\in V(G)$ as the set of all colors appearing on edges incident with $v$. The palette index $\check{s}(G)$ of $G$ is the minimum number of distinct palettes occurring in a proper edge coloring of $G$. A graph $G$ is called nearly bipartite if there exists $ v\in V(G)$ so that $G-v$ is a bipartite graph. In this paper, we give an upper bound on the palette index of a nearly bipartite graph $G$ by using the decomposition of $G$ into cycles. We also provide an upper bound on the palette index of Cartesian products of graphs. In particular, we show that for any graphs $G$ and $H$, $\check{s}(G\square H)\leq \check{s}(G)\check{s}(H)$.