Abstract
For a graph G, the signless Laplacian matrix Q(G) is defined as Q(G)=D(G)+A(G), where A(G) is the adjacency matrix of G and D(G) the diagonal matrix whose main entries are the degrees of the vertices in G. The Q-spectrum of G is that of Q(G). In the present paper, we are interested in the minimum values of the second largest signless Laplacian eigenvalue q2(G) of a connected graph G. We find the five smallest values of q2(G) over the set of connected graphs G with given order n. We also characterize the corresponding extremal graphs.
Original language | English |
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Pages (from-to) | 46-51 |
Number of pages | 6 |
Journal | Discrete Applied Mathematics |
Volume | 306 |
DOIs | |
Publication status | Published - Jan 15 2022 |
Keywords
- Extremal graph
- Lower bound
- Second largest eigenvalue
- Signless Laplacian
ASJC Scopus subject areas
- Discrete Mathematics and Combinatorics
- Applied Mathematics