Zobrazeno 1 - 10
of 42
pro vyhledávání: '"Allem, Luiz Emilio"'
Autor:
Allem, Luiz Emilio, Braga, Rodrigo Orsini, Hoppen, Carlos, Oliveira, Elismar da Rosa, Sibemberg, Lucas Siviero, Trevisan, Vilmar
Given a tree $T$, let $q(T)$ be the minimum number of distinct eigenvalues in a symmetric matrix whose underlying graph is $T$. It is well known that $q(T)\geq d(T)+1$, where $d(T)$ is the diameter of $T$, and a tree $T$ is said to be diminimal if $q
Externí odkaz:
http://arxiv.org/abs/2302.00835
A graph is said to be I-eigenvalue free if it has no eigenvalues in the interval I with respect to the adjacency matrix A. In this paper we present two algorithms for generating I-eigenvalue free threshold graphs.
Comment: 23 figures, 23 pages
Comment: 23 figures, 23 pages
Externí odkaz:
http://arxiv.org/abs/2110.12107
The aim of this paper is to analyse the evolution of the COVID-19 pandemic in Rio Grande do Sul by applying graph-theoretical tools, particularly spectral clustering techniques, on weighted graphs defined on the set of 167 municipalities in the state
Externí odkaz:
http://arxiv.org/abs/2008.00333
Autor:
Allem, Luiz Emilio, Jaume, Daniel Alejandro, Molina, Gonzalo, Toledo, Maikon Machado, Trevisan, Vilmar
In this work we obtain basis for the null space of unicyclic graphs. We extend the null decomposition of trees from [11] for unicyclic graphs. As an application, we obtain closed formulas for the independence and matching numbers of unicyclic graphs
Externí odkaz:
http://arxiv.org/abs/1907.08618
Autor:
Allem, Luiz Emilio, Jaume, Daniel Alejandro, Molina, Gonzalo, Toledo, Maikon Machado, Trevisan, Vilmar
We characterize unicyclic graphs that are singular using the support of the null space of their pendant trees. From this, we obtain closed formulas for the independence and matching numbers of a unicyclic graph, based on the support of its subtrees.
Externí odkaz:
http://arxiv.org/abs/1907.07650
Autor:
Allem, Luiz Emilio, Tura, Fernando
A graph is called integral if all the eigenvalues of its adjacency matrix are integers. In this paper, we show a cograph that has a balanced cotree $T_{G}(a_{1},\ldots,a_{r-1},0|0,\ldots,0,a_{r})$ is integral computing its spectrum. As an application
Externí odkaz:
http://arxiv.org/abs/1902.06817
In this paper, we consider the Randi\'{c} energy $RE$ of simple connected graphs. We provide upper bounds for $RE$ in terms of the number of vertices and the nullity of the graph. We present families of graphs that satisfy the Conjecture proposed by
Externí odkaz:
http://arxiv.org/abs/1811.08776
Autor:
Allem, Luiz Emilio, Tura, Fernando
Motivated by the linear time algorithm that locates the eigenvalues of a cograph G [10], we investigate the multiplicity of eigenvalue for \lambda \neq -1,0. For cographs with balanced cotrees we determine explicitly the highest value for the multipl
Externí odkaz:
http://arxiv.org/abs/1801.08972
Autor:
Allem, Luiz Emilio, Capaverde, Juliane, Trevisan, Vilmar, Gutman, Ivan, Zogić, Emir, Glogić, Edin
The resolvent energy of a graph $G$ of order $n$ is defined as $ER=\sum_{i=1}^n (n-\lambda_i)^{-1}$, where $\lambda_1,\lambda_2,\ldots,\lambda_n$ are the eigenvalues of $G$. In a recent work [Gutman et al., {\it MATCH Commun. Math. Comput. Chem.\/} {
Externí odkaz:
http://arxiv.org/abs/1512.08938
Autor:
Allem, Luiz Emilio, Tura, Fernando
Publikováno v:
In Discrete Applied Mathematics 15 September 2020 283:153-167
