55 citations · 204 across the 46 of their papers we have counts for
8 papers · 1 filter
An algebraic approach to lifts of digraphs
C. Dalfó, M. A. Fiol, M. Miller +2
We study the relationship between two key concepts in the theory of (di)graphs: the quotient digraph, and the lift of a base (voltage) digraph. These techniques contract or e…
Graphs, friends and acquaintances
C. Dalfó, M. A. Fiol
As is well known, a graph is a mathematical object modeling the existence of a certain relation between pairs of elements of a given set. Therefore, it is not surprising that many…
An improved Moore bound for mixed graphs
C. Dalfó, M. A. Fiol, N. López
A mixed graph can contain both (undirected) edges and arcs (directed edges). Here we derive an improved Moore-like bound for the maximum number of vertices of a mixed graph wit…
On middle cube graphs
C. Dalfó, M. A. Fiol, M. Mitjana
We study a family of graphs related to the -cube. The middle cube graph of parameter is the subgraph of induced by the set of vertices whose binary representation…
Sequence mixed graphs
C. Dalfó, M. A. Fiol, N. López
A mixed graph can be seen as a type of digraph containing some edges (two opposite arcs). Here we introduce the concept of sequence mixed graphs, which is a generalization of both…
The spectral excess theorem for graphs with few eigenvalues whose distance- or distance--or- graph is strongly regular
C. Dalfó, M. A. Fiol, J. Koolen
We study regular graphs whose distance- graph or distance--or- graph is strongly regular. We provide a characterization of such graphs (among regular graphs with few d…