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http://hdl.handle.net/10773/4309
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DC Field | Value | Language |
---|---|---|
dc.contributor.author | Cardoso, D.M. | pt |
dc.contributor.author | Rama, P. | pt |
dc.date.accessioned | 2011-11-10T10:47:20Z | - |
dc.date.issued | 2007 | - |
dc.identifier.issn | 0024-3795 | pt |
dc.identifier.uri | http://hdl.handle.net/10773/4309 | - |
dc.description.abstract | Graphs with (k, τ)-regular sets and equitable partitions are examples of graphs with regularity constraints. A (k, τ)-regular set of a graph G is a subset of vertices S ⊆ V(G) inducing a k-regular subgraph and such that each vertex not in S has τ neighbors in S. The existence of such structures in a graph provides some information about the eigenvalues and eigenvectors of its adjacency matrix. For example, if a graph G has a (k1, τ1)-regular set S1 and a (k2, τ2)-regular set S2 such that k1 - τ1 = k2 - τ2 = λ, then λ is an eigenvalue of G with a certain eigenvector. Additionally, considering primitive strongly regular graphs, a necessary and sufficient condition for a particular subset of vertices to be (k, τ)-regular is introduced. Another example comes from the existence of an equitable partition in a graph. If a graph G, has an equitable partition π then its line graph, L(G), also has an equitable partition, over(π, ̄), induced by π, and the adjacency matrix of the quotient graph L (G) / over(π, ̄) is obtained from the adjacency matrix of G/π. © 2006 Elsevier Inc. All rights reserved. | pt |
dc.description.sponsorship | CEOC | pt |
dc.description.sponsorship | FCT | pt |
dc.description.sponsorship | FEDER | pt |
dc.language.iso | eng | pt |
dc.publisher | Elsevier | pt |
dc.relation.uri | http://www.scopus.com/inward/record.url?eid=2-s2.0-33947155212&partnerID=40&md5=a93ca233444e7b7ca4feb3a981fc68cd | - |
dc.rights | restrictedAccess | por |
dc.subject | Equitable partitions | pt |
dc.subject | Graph spectra | pt |
dc.subject | Graph theory | pt |
dc.subject | Strongly regular graphs | pt |
dc.subject | Constrained optimization | pt |
dc.subject | Eigenvalues and eigenfunctions | pt |
dc.subject | Matrix algebra | pt |
dc.title | Spectral results on graphs with regularity constraints | pt |
dc.type | article | pt |
dc.peerreviewed | yes | pt |
ua.distribution | international | pt |
degois.publication.firstPage | 90 | pt |
degois.publication.issue | 1 | pt |
degois.publication.issue | 1 | - |
degois.publication.lastPage | 98 | pt |
degois.publication.title | Linear Algebra and Its Applications | pt |
degois.publication.volume | 423 | pt |
dc.date.embargo | 10000-01-01 | - |
dc.relation.publisherversion | http://www.sciencedirect.com/science/article/pii/S0024379506004526 | * |
Appears in Collections: | DMat - Artigos |
Files in This Item:
File | Description | Size | Format | |
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LAA-CardosoRama2007.pdf | Versão Electrónica | 169.36 kB | Adobe PDF |
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