Now showing items 1-4 of 4

    • A note on the order of iterated line digraphs 

      Dalfó, Cristina; Fiol, Miguel Angel (Wiley Periodicals Inc., 2016-06)
      Given a digraph G, we propose a new method to find therecurrence equation for the number of vertices nk of the k-iterated linedigraph Lk(G), for k≥0, where L0(G)=G. We obtain this result by usingthe minimal polynomial of ...
    • An algebraic approach to lifts of digraphs 

      Dalfó, Cristina; Fiol, Miguel Angel; Miller, Mirka; Ryan, Joe; Sirán, Jozef (Elsevier, 2018)
      We present some applications of a new matrix approach for studying the properties of the lift of a voltage digraph, which has arcs weighted by the elements of a group. As a main result, when the involved group is Abelian, ...
    • Spectra and eigenspaces from regular partitions of Cayley (di)graphs of permutation groups 

      Dalfó, Cristina; Fiol, Miguel Angel (Elsevier, 2020)
      In this paper, we present a method to obtain regular (or equitable) partitions of Cayley (di)graphs (that is, graphs, digraphs, or mixed graphs) of permutation groups on n letters. We prove that every partition of the ...
    • The spectra of lifted digraphs 

      Dalfó, Cristina; Fiol, Miguel Angel; Sirán, Jozef (Springer, 2019-01-02)
      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 ...