5 papers
On factored lifts of graphs and their spectra
C. Dalfó, M. A. Fiol, S. PavlÃková +1
In this note, we introduce the concept of factored lift, associated with a combined voltage graph, as a generalization of the lift graph. We present a new method for computing the…
A general method to find the spectrum and eigenspaces of the -token of a cycle, and 2-token through continuous fractions
M. A. Reyes, C. Dalfó, M. A. Fiol +1
The -token graph of a graph is the graph whose vertices are the -subsets of vertices from , two of which being adjacent whenever their symmetric difference is…
On bipartite -mixed graphs
C. Dalfó, G. Erskine, G. Exoo +2
Mixed graphs can be seen as digraphs with arcs and edges (or digons, that is, two opposite arcs). In this paper, we consider the case where such graphs are bipartite and in which t…
On token signed graphs
C. Dalfó, M. A. Fiol, E. Steffen
We introduce the concept of a -token signed graph and study some of its combinatorial and algebraic properties. We prove that two switching isomorphic signed graphs have switchi…
Note on the product of the largest and the smallest eigenvalue of a graph
Aida Abiad, Cristina Dalfó, Miquel Ãngel Fiol
In this note, we use eigenvalue interlacing to derive an inequality between the maximum degree of a graph and its maximum and minimum adjacency eigenvalues. The case of equality is…