منابع مشابه
Graphs cospectral with starlike trees
A tree which has exactly one vertex of degree greater than two is said to be starlike. In spite of seemingly simple structure of these trees, not much is known about their spectral properties. In this paper, we introduce a generalization of the notion of cospectrality called m-cospectrality which turns out to be useful in constructing cospectral graphs. Based on this, we construct cospectral ma...
متن کاملNo Starlike Trees Are Laplacian Cospectral
Let G be a graph with n vertices and m edges. The degree sequence of G is denoted by d1 ≥ d2 ≥ · · · ≥ dn. Let A(G) and D(G) = diag(di : 1 ≤ i ≤ n) be the adjacency matrix and the degree diagonal matrix of G, respectively. The Laplacian matrix of G is L(G) = D(G) − A(G). It is well known that L(G) is a symmetric, semidefinite matrix. We assume the spectrum of L(G), or the Laplacian spectrum of ...
متن کاملEnumeration of cospectral graphs
We have enumerated all graphs on at most 11 vertices and determined their spectra with respect to various matrices, such as the adjacency matrix and the Laplacian matrix. We have also counted the numbers for which there is at least one other graph with the same spectrum (a cospectral mate). In addition we consider a construction for pairs of cospectral graphs due to Godsil and McKay, which we c...
متن کاملMatchings in starlike trees
1. I N T R O D U C T I O N Ordering of graphs with respect to the number of matchings, and finding the graphs extremal with regard to this property, has been the topic of several earlier works [1-4]. These results have chemical applications, in connection with the so-called total 1r-electron energy [5-7]. Let G be a graph without loops and multiple edges. For k being a positive integer, m ( G ,...
متن کاملCospectral Graphs on 12 Vertices
We found the characteristic polynomials for all graphs on 12 vertices, and report statistics related to the number of cospectral graphs.
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Linear Algebra and its Applications
سال: 2008
ISSN: 0024-3795
DOI: 10.1016/j.laa.2008.01.001