Cospectral digraphs from locally line digraphs

A digraph Γ =(V, E) is a line digraph when every pair of vertices u, v∈V have either equal or disjoint in-neighborhoods. When this condition only applies for vertices in a given subset (with at least two elements), we say that Γ is a locally line digraph. In this paper we give a new method to obtain...

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Bibliographic Details
Authors: Dalfó, Cristina, Fiol Mora, Miguel Ángel
Format: article
Status:Versión aceptada para publicación
Publication Date:2016
Country:España
Institution:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
Repository:Recercat. Dipósit de la Recerca de Catalunya
OAI Identifier:oai:recercat.cat:10459.1/72568
Online Access:https://doi.org/10.1016/j.laa.2016.03.014
http://hdl.handle.net/10459.1/72568
Access Level:Open access
Keyword:Digraph
Adjacency matrix
Spectrum
Cospectral digraph
Diameter
De Bruijn digraph
Kautz digraph
Description
Summary:A digraph Γ =(V, E) is a line digraph when every pair of vertices u, v∈V have either equal or disjoint in-neighborhoods. When this condition only applies for vertices in a given subset (with at least two elements), we say that Γ is a locally line digraph. In this paper we give a new method to obtain a di-graph Γ′ cospectral with a given locally line digraph Γ with diameter D, where the diameter D′ of Γ′ is in the interval [D−1, D+1]. In particular, when the method is applied to De Bruijn or Kautz digraphs, we obtain cospectral digraphs with the same algebraic properties that characterize the formers.