Edge distance-regular graphs

Edge-distance-regularity is a concept recently introduced by the authors which is similar to that of distance-regularity, but now the graph is seen from each of its edges instead of from its vertices. More precisely, a graph Γ with adjacency matrix A is edge-distance-regular when it is distance-regu...

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Autores: Cámara Vallejo, Marc; Dalfó, Cristina; Fàbrega Canudas, José; Fiol Mora, Miguel Ángel; Garriga, Ernest
Tipo de documento: Artigo
Estado:Accepted version
Data de publicação:2011
País:España
Recursos:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
Repositório:Recercat. Dipósit de la Recerca de Catalunya
OAI Identifier:oai:recercat.cat:10459.1/72557
Acesso em linha:https://doi.org/10.1016/j.endm.2011.09.037
http://hdl.handle.net/10459.1/72557
Nível de acesso:Acesso aberto
Palavra-chave:Distance-regularity
Local spectra
Predistance polynomials
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author Cámara Vallejo, Marc
author2 Dalfó, Cristina
Fàbrega Canudas, José
Fiol Mora, Miguel Ángel
Garriga, Ernest
author2_role author
author
author
author
author_browse Cámara Vallejo, Marc
Dalfó, Cristina
Fiol Mora, Miguel Ángel
Fàbrega Canudas, José
Garriga, Ernest
author_facet Cámara Vallejo, Marc
Dalfó, Cristina
Fàbrega Canudas, José
Fiol Mora, Miguel Ángel
Garriga, Ernest
author_role author
collection Recercat. Dipósit de la Recerca de Catalunya
description Edge-distance-regularity is a concept recently introduced by the authors which is similar to that of distance-regularity, but now the graph is seen from each of its edges instead of from its vertices. More precisely, a graph Γ with adjacency matrix A is edge-distance-regular when it is distance-regular around each of its edges and with the same intersection numbers for any edge taken as a root. In this paper we study this concept, give some of its properties, such as the regularity of Γ, and derive some characterizations. In particular, it is shown that a graph is edge-distance-regular if and only if its k-incidence matrix is a polynomial of degree k in A multiplied by the (standard) incidence matrix. Also, the analogue of the spectral excess theorem for distance-regular graphs is proved, so giving a quasi-spectral characterization of edge-distance-regularity. Finally, it is shown that every nonbipartite graph which is both distance-regular and edge-distance-regular is a generalized odd graph.
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institution Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
instname_str Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
network_acronym_str ES
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oai_identifier_str oai:recercat.cat:10459.1/72557
publishDate 2011
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publisher Elsevier
publisherStr Elsevier
reponame_str Recercat. Dipósit de la Recerca de Catalunya
spelling Edge distance-regular graphs Cámara Vallejo, Marc Dalfó, Cristina Fàbrega Canudas, José Fiol Mora, Miguel Ángel Garriga, Ernest Distance-regularity Local spectra Predistance polynomials Edge-distance-regularity is a concept recently introduced by the authors which is similar to that of distance-regularity, but now the graph is seen from each of its edges instead of from its vertices. More precisely, a graph Γ with adjacency matrix A is edge-distance-regular when it is distance-regular around each of its edges and with the same intersection numbers for any edge taken as a root. In this paper we study this concept, give some of its properties, such as the regularity of Γ, and derive some characterizations. In particular, it is shown that a graph is edge-distance-regular if and only if its k-incidence matrix is a polynomial of degree k in A multiplied by the (standard) incidence matrix. Also, the analogue of the spectral excess theorem for distance-regular graphs is proved, so giving a quasi-spectral characterization of edge-distance-regularity. Finally, it is shown that every nonbipartite graph which is both distance-regular and edge-distance-regular is a generalized odd graph. Supported by the Ministry of Science and Innovation of Spain under project MTM2008- 06620-C03-01 and by the Catalan Research Council under project 2009SGR01387 Elsevier https://doi.org/10.1016/j.endm.2011.09.037 http://hdl.handle.net/10459.1/72557
spellingShingle Edge distance-regular graphs
Cámara Vallejo, Marc
Distance-regularity
Local spectra
Predistance polynomials
status_str acceptedVersion
title Edge distance-regular graphs
title_full Edge distance-regular graphs
title_fullStr Edge distance-regular graphs
title_full_unstemmed Edge distance-regular graphs
title_short Edge distance-regular graphs
title_sort Edge distance-regular graphs
topic Distance-regularity
Local spectra
Predistance polynomials
topic_facet Distance-regularity
Local spectra
Predistance polynomials
url https://doi.org/10.1016/j.endm.2011.09.037
http://hdl.handle.net/10459.1/72557