L. D. de Lima

activity

20122026

most citedOn the second largest eigenvalue of the signless Laplacian

24 citations · 25 across the 5 of their papers we have counts for

collaborators

6 papers

math.SP2026

Graph transformations and eigenvectors of the Laplacian, signless Laplacian and Adjacency matrices

Jean-Guy Caputo, Leonardo de Lima, Arnaud Knippel

We study graph transformations and their effects on the eigenvectors of three fundamental graph matrices: the adjacency matrix $A$ , the signless Laplacian $Q$ , and the Laplacian $L…

math.CO2026

Distribution of signless Laplacian eigenvalues and degree sequence

Saieed Akbari, M. Darougheh, L. S. de Lima +1

Let $G$ be a graph of order $n$ with degree sequence $d_{1} \geq \dots \geq d_{n}$ . Let $m_{G} I$ be the number of signless Laplacian eigenvalues in an interval $I$ . In this paper, w…

math.CO2015★ 1 cited

The clique number and the smallest Q-eigenvalue of graphs

Leonardo de Lima, Vladimir Nikiforov, Carla Oliveira

Let $q_{m i n} (G)$ stand for the smallest eigenvalue of the signless Laplacian of a graph $G$ of order $n .$ This paper gives some results on the following extremal problem: How larg…

math.SP2014

A lower bound for the sum of the two largest signless Laplacian eigenvalues

Leonardo de Lima, Carla Oliveira

Let $G$ be a graph of order $n \geq 3$ with sequence degree given as $d_{1} (G) \geq ... \geq d_{n} (G)$ and let $μ_{1} (G), ..., μ_{n} (G)$ and $q_{1} (G), ..., q_{n} (G)$ be the Laplacian and…

math.SP2014

Spectra of the blow-up graphs

Carla Oliveira, Leonardo de Lima, Vladimir Nikiforov

Let $G$ be graph on $n$ vertices and $G^{(t)}$ its blow-up graph of order $t .$ In this paper, we determine all eigenvalues of the Laplacian and the signless Laplacian matrix of $G^…

math.SP2012★ 24 cited

On the second largest eigenvalue of the signless Laplacian

Leonardo S. de Lima, Vladimir Nikiforov

Let $G$ be a graph of order $n,$ and let $q_{1} (G) \geq ... \geq q_{n} (G)$ be the eigenvalues of the $Q$ -matrix of $G$ , also known as the signless Laplacian of $G .$ In this paper w…