A Lower Bound for the Radio Number of Graphs

Autor: Devsi Bantva
Rok vydání: 2019
Předmět:
Zdroj: Algorithms and Discrete Applied Mathematics ISBN: 9783030115081
CALDAM
DOI: 10.1007/978-3-030-11509-8_14
Popis: A radio labeling of a graph G is a mapping \(\varphi : V(G) \rightarrow \{0, 1, 2,\ldots \}\) such that \(|\varphi (u)-\varphi (v)|\ge \mathrm{diam}(G) + 1 - d(u,v)\) for every pair of distinct vertices u, v of G, where \(\mathrm{diam}(G)\) and d(u, v) are the diameter of G and distance between u and v in G, respectively. The radio number \(\mathrm{rn}(G)\) of G is the smallest number k such that G has radio labeling with \(\max \{\varphi (v):v \in V(G)\} = k\). In this paper, we slightly improve the lower bound for the radio number of graphs given by Das et al. in [5] and, give necessary and sufficient condition to achieve the lower bound. Using this result, we determine the radio number for cartesian product of paths \(P_{n}\) and the Peterson graph P. We give a short proof for the radio number of cartesian product of paths \(P_{n}\) and complete graphs \(K_{m}\) given by Kim et al. in [6].
Databáze: OpenAIRE