Algebraic conditions for -tough graphs
We give some algebraic conditions for -tough graphs in terms of the Laplacian eigenvalues and adjacency eigenvalues of graphs.
Bo Lian Liu, Siyuan Chen (2010)
Czechoslovak Mathematical Journal
We give some algebraic conditions for -tough graphs in terms of the Laplacian eigenvalues and adjacency eigenvalues of graphs.
Stephen J. Kirkland, Israel Rocha, Vilmar Trevisan (2015)
Czechoslovak Mathematical Journal
Let be a -connected graph with . A hinge is a subset of vertices whose deletion from yields a disconnected graph. We consider the algebraic connectivity and Fiedler vectors of such graphs, paying special attention to the signs of the entries in Fiedler vectors corresponding to vertices in a hinge, and to vertices in the connected components at a hinge. The results extend those in Fiedler’s papers Algebraic connectivity of graphs (1973), A property of eigenvectors of nonnegative symmetric...
Robert Grone, Russell Merris (1987)
Czechoslovak Mathematical Journal
Berman, A., Förster, K.-H. (2005)
ELA. The Electronic Journal of Linear Algebra [electronic only]
Olga Bodroža-Pantić (1997)
Publications de l'Institut Mathématique
Jadwiga Dzikiewicz, M. M. Sysło (1978)
Applicationes Mathematicae
Dragan Stevanović (2005)
Mathematica Bohemica
We find all connected graphs in which any two distinct vertices have exactly two common neighbors, thus solving a problem by B. Zelinka.
Fiol, M.A. (1997)
The Electronic Journal of Combinatorics [electronic only]
Carlos Martins da Fonseca (2011)
Czechoslovak Mathematical Journal
In this short note we provide an extension of the notion of Hessenberg matrix and observe an identity between the determinant and the permanent of such matrices. The celebrated identity due to Gibson involving Hessenberg matrices is consequently generalized.
Kirkland, S. (2001)
ELA. The Electronic Journal of Linear Algebra [electronic only]
Hong-Hai Li, Jiong-Sheng Li (2008)
Discussiones Mathematicae Graph Theory
In this paper, we established a connection between the Laplacian eigenvalues of a signed graph and those of a mixed graph, gave a new upper bound for the largest Laplacian eigenvalue of a signed graph and characterized the extremal graph whose largest Laplacian eigenvalue achieved the upper bound. In addition, an example showed that the upper bound is the best in known upper bounds for some cases.
D. Defays (1978)
Mathématiques et Sciences Humaines
Harishchandra S. Ramane, Ivan Gutman, Hanumappa B. Walikar, Sabeena B. Halkarni (2004)
Kragujevac Journal of Mathematics
Dragoš Cvetković (2009)
Zbornik Radova
Dragoš Cvetković (2011)
Zbornik Radova
Dragan Stevanović (2011)
Zbornik Radova
H. Schneider, M.v. Golitschek (1984)
Numerische Mathematik
Sivasubramanian, Sivaramakrishnan (2005)
ELA. The Electronic Journal of Linear Algebra [electronic only]
Song Liang, Nobuaki Obata, Shuji Takahashi (2007)
Banach Center Publications
Motivated by the Watts-Strogatz model for a complex network, we introduce a generalization of the Erdős-Rényi random graph. We derive a combinatorial formula for the moment sequence of its spectral distribution in the sparse limit.
Daisuke Igarashi, Nobuaki Obata (2006)
Banach Center Publications
Two new examples are given for illustrating the method of quantum decomposition in the asymptotic spectral analysis for a growing family of graphs. The odd graphs form a growing family of distance-regular graphs and the two-sided Rayleigh distribution appears in the limit of vacuum spectral distribution of the adjacency matrix. For a spidernet as well as for a growing family of spidernets the vacuum distribution of the adjacency matrix is the free Meixner law. These distributions are calculated...