# DMGT

ISSN 1234-3099 (print version)

ISSN 2083-5892 (electronic version)

# IMPACT FACTOR 2018: 0.741

SCImago Journal Rank (SJR) 2018: 0.763

Rejection Rate (2018-2019): c. 84%

# Discussiones Mathematicae Graph Theory

## ORDER UNICYCLIC GRAPHS ACCORDING TO SPECTRAL RADIUS OF UNORIENTED LAPLACIAN MATRIX

 Yi-Zheng Fan Key Laboratory of Intelligent Computing & Signal Processing Ministry of Education of the People's Republic of China Anhui University, Hefei 230039, P.R. China e-mail: fanyz@ahu.edu.cn Song Wu School of Mathematics and Computation Sciences Anhui University, Hefei, Anhui 230039, P.R. China

## Abstract

The spectral radius of a graph is defined by that of its unoriented Laplacian matrix. In this paper, we determine the unicyclic graphs respectively with the third and the fourth largest spectral radius among all unicyclic graphs of given order.

Keywords: unicyclic graph, Laplacian matrix, spectral radius.

2000 Mathematics Subject Classification: 05C50, 15A18.

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