The spectra of lifted digraphs

We present a method to derive the complete spectrum of the lift Γα of a base digraph Γ , with voltage assignment α on a (finite) group G. The method is based on assigning to Γ a quotient-like matrix whose entries are elements of the group algebra C[G] , which fully represents Γα . This allows us to...

Descripción completa

Detalles Bibliográficos
Autores: Dalfó, Cristina, Fiol Mora, Miguel Ángel, Sirán, Jozef
Tipo de recurso: artículo
Estado:Versión aceptada para publicación
Fecha de publicación:2019
País:España
Institución:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
Repositorio:Recercat. Dipósit de la Recerca de Catalunya
OAI Identifier:oai:recercat.cat:10459.1/67512
Acceso en línea:https://doi.org/10.1007/s10801-018-0862-y
http://hdl.handle.net/10459.1/67512
Access Level:acceso abierto
Palabra clave:Digraph
Adjacency matrix
Regular partition
Quotient digraph
Spectrum
Lifted digraph
Descripción
Sumario:We present a method to derive the complete spectrum of the lift Γα of a base digraph Γ , with voltage assignment α on a (finite) group G. The method is based on assigning to Γ a quotient-like matrix whose entries are elements of the group algebra C[G] , which fully represents Γα . This allows us to derive the eigenvectors and eigenvalues of the lift in terms of those of the base digraph and the irreducible characters of G. Thus, our main theorem generalizes some previous results of Lovász and Babai concerning the spectra of Cayley digraphs.