scholarly journals On unicyclic graphs whose second largest eigenvalue dose not exceed 1

2004 ◽  
Vol 136 (1) ◽  
pp. 117-124 ◽  
Author(s):  
Guang-Hui Xu
2021 ◽  
Vol 10 (1) ◽  
pp. 131-152
Author(s):  
Stephen Drury

Abstract We discuss the question of classifying the connected simple graphs H for which the second largest eigenvalue of the signless Laplacian Q(H) is ≤ 4. We discover that the question is inextricable linked to a knapsack problem with infinitely many allowed weights. We take the first few steps towards the general solution. We prove that this class of graphs is minor closed.


2016 ◽  
pp. n/a-n/a
Author(s):  
Weijia Xue ◽  
Tingting Lin ◽  
Xin Shun ◽  
Fenglei Xue ◽  
Xuejia Lai

2019 ◽  
Vol 19 (04) ◽  
pp. 2050068
Author(s):  
Hezan Huang ◽  
Bo Zhou

The distance spectral radius of a connected graph is the largest eigenvalue of its distance matrix. For integers [Formula: see text] and [Formula: see text] with [Formula: see text], we prove that among the connected graphs on [Formula: see text] vertices of given maximum degree [Formula: see text] with at least one cycle, the graph [Formula: see text] uniquely maximizes the distance spectral radius, where [Formula: see text] is the graph obtained from the disjoint star on [Formula: see text] vertices and path on [Formula: see text] vertices by adding two edges, one connecting the star center with a path end, and the other being a chord of the star.


1995 ◽  
Vol 138 (1-3) ◽  
pp. 213-227 ◽  
Author(s):  
Dragoš Cvetković ◽  
Slobodan Simić

Author(s):  
Drasko Tomic ◽  
Karolj Skala ◽  
Lado Kranjcevic ◽  
Boris Pirkic ◽  
Sanja Stifter ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document