On the eigenvalues of firefly graphs

Abstract

The sharp upper bounds and the sharp lower bounds of the largest‎ ‎eigenvalues $lambda_1$‎, ‎the least eigenvalue $lambda_n$‎, ‎the second largest eigenvalue $lambda_2$‎, ‎the spread and the‎ ‎separator among all firefly graphs on $n$ vertices are determined‎.