Spanning graphs of hypercubes: starlike and double starlike trees
نویسندگان
چکیده
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...
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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 ,...
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Double integral operators which were considered by S. S. Miller and P. T. Mocanu Integral Transform. Spec. Funct. 19 2008 , 591–597 are discussed. In order to show the analytic function f z is starlike of order β in the open unit disk U, the theory of differential subordinations for analytic functions is applied. The object of the present paper is to discuss some interesting conditions for f z ...
متن کاملSome Spectral Properties of Starlike Trees
A b s t r a c t. A tree is said to be starlike if exactly one of its vertices has degree greater than two. We show that almost all starlike trees are hyperbolic, and determine all exceptions. If k is the maximal vertex degree of a starlike tree and λ 1 is its largest eigenvalue, then √ k ≤ λ 1 < k/ √ k − 1. A new way to characterize integral starlike trees is put forward.
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 ...
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ژورنال
عنوان ژورنال: Discrete Mathematics
سال: 2002
ISSN: 0012-365X
DOI: 10.1016/s0012-365x(01)00086-3