Regular graphs with four eigenvalues
نویسندگان
چکیده
منابع مشابه
Small regular graphs with four eigenvalues
For most feasible spectra of connected regular graphs with four distinct eigenvalues and at most 30 vertices we find all such graphs, using both theoretic and computer results. @ 1998 Elsevier Science B.V. All rights reserved AMS classijication: primary 05C30; secondary 05E99
متن کاملRegular Factors of Regular Graphs from Eigenvalues
Let r and m be two integers such that r > m. Let H be a graph with order |H|, size e and maximum degree r such that 2e > |H|r−m. We find a best lower bound on spectral radius of graph H in terms of m and r. Let G be a connected r-regular graph of order |G| and k < r be an integer. Using the previous results, we find some best upper bounds (in terms of r and k) on the third largest eigenvalue th...
متن کاملGraphs with four distinct Laplacian eigenvalues
In this paper, we investigate connected nonregular graphs with four distinct Laplacian eigenvalues. We characterize all such graphs which are bipartite or have exactly one multiple Laplacian eigenvalue. Other examples of interest are also presented.
متن کاملPerfect matchings in regular graphs from eigenvalues
Throughout, G denotes a simple graph of order n (the number of vertices) and size e (the number of edges). The eigenvalues of G are the eigenvalues λi 1 Research partially supported by an NSERC postdoctoral fellowship. 2 Research supported by the Natural Sciences and Engineering Research Council of Canada. Email addresses: [email protected] (Sebastian M. Cioabă), [email protected] (D...
متن کاملTight estimates for eigenvalues of regular graphs
It is shown that if a d-regular graph contains s vertices so that the distance between any pair is at least 4k, then its adjacency matrix has at least s eigenvalues which are at least 2 √ d − 1 cos( π 2k ). A similar result has been proved by Friedman using more sophisticated tools.
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: 1995
ISSN: 0024-3795
DOI: 10.1016/0024-3795(94)00346-f