In this paper, we determine graphs with the largest spectral radius among all the tricyclic graphs with n vertices and k pendent vertices. © 2008 Elsevier Inc. All rights reserved. AMS classification: 05C50; 05C35

Let Tn be the class of tricyclic graphs on n vertices. In this paper, a sharp lower bound for the total number of matchings of graphs in Tn is determined.

In this paper, we determine the tight upper bound for the number of matchings of connected n-vertex tricyclic graphs. We show that this bound is 13fn−4+16fn−5, where fn be the nth Fibonacci number. We also characterize the n-vertex simple connected tricyclic graph for which the bound is best possible.

The forgotten topological index of a molecular graph $G$ is defined as $F(G)=sum_{vin V(G)}d^{3}(v)$, where $d(u)$ denotes the degree of vertex $u$ in $G$. The first through the sixth smallest forgotten indices among all trees, the first through the third smallest forgotten indices among all connected graph with cyclomatic number $gamma=1,2$, the first through<br /...

It is well known that the graph invariant, ‘the Merrifield–Simmons index’ is important one in structural chemistry. The connected acyclic graphs with maximal and minimal Merrifield–Simmons indices are determined by Prodinger and Tichy [H. Prodinger, R.F. Tichy, Fibonacci numbers of graphs, Fibonacci Quart. 20 (1982) 16–21]. The sharp upper and lower bounds for theMerrifield–Simmons indices of u...