D. Cardoso

activity

20182022

collaborators

7 papers

math.CO2022

Sharp bounds on the least eigenvalue of a graph determined from edge clique partitions

Domingos M. Cardoso, Inês Serôdio Costa, Rui Duarte

Sharp bounds on the least eigenvalue of an arbitrary graph are presented. Necessary and sufficient (just sufficient) conditions for the lower (upper) bound to be attained are deduc…

math.CO2021

On the Randić energy of caterpillar graphs

Domingos M. Cardoso, Paula Carvalho, Roberto C. Díaz +1

A caterpillar graph $T (p_{1}, \dots, p_{r})$ of order $n = r + \sum_{i = 1}^{r} p_{i}$ , $r \geq 2$ , is a tree such that removing all its pendent vertices gives rise to a path of order $r$ . In t…

math.CO2021

The H-join of arbitrary families of graphs

Domingos M. Cardoso, Helena Gomes, Sofia J. Pinheiro

The $H$ -join of a family of graphs $G = {G_{1}, \dots, G_{p}}$ , also called the generalized composition, $H [G_{1}, \dots, G_{p}]$ , where all graphs are undirected, simple and fin…

math.CO2020

Spectral properties of the $n$ -Queens' Graphs

Domingos M. Cardoso, Inês Serôdio Costa, Rui Duarte

The $n$ -Queens' graph, $Q (n)$ , is the graph associated to the $n \times n$ chessboard (a generalization of the classical $8 \times 8$ chessboard), with $n^{2}$ vertices, ea…

math.CO2020

The main vertices of a star set and related graph parameters

Milica Anđelić, Domingos M. Cardoso, Slobodan K. Simi\' c +1

A vertex $v \in V (G)$ is called $λ$ -main if it belongs to a star set $X \subset V (G)$ of the eigenvalue $λ$ of a graph $G$ and this eigenvalue is main for the graph obtained from $…

math.CO2018

An overview of $(κ, τ)$ -regular sets and their applications

Domingos M. Cardoso

A ( $κ$ , $τ$ )-regular set is a vertex subset S inducing a $κ$ -regular subgraph such that every vertex out of S has $τ$ neighbors in S. This article is an expository overview of the m…