arXiv subjects

Pedro Montealegre

Publications and source records attributed to Pedro Montealegre.

40 records · Page 3Linked to original sources

arXiv2016

On Distance-$d$ Independent Set and other problems in graphs with few minimal separators

Fomin and Villanger (STACS 2010) proved that Maximum Independent Set, Feedback Vertex Set, and more generally the problem of finding a maximum induced subgraph of treewith at most a constant $t$, can be solved in polynomial time on graph classes with polynomially many minimal separators. We extend these results in two directions. Let $\Gpoly$ be the class of graphs with at most $\poly(n)$ minimal separators, for some polynomial $\poly$. We show that the odd powers of a graph $G$ have at most as many minimal separators as $G$. Consequently, \textsc{Distance-$d$ Independent Set}, which consists in finding maximum set of vertices at pairwise distance at least $d$, is polynomial on $\Gpoly$, for any even $d$. The problem is NP-hard on chordal graphs for any odd $d \geq 3$. We also provide polynomial algorithms for Connected Vertex Cover and Connected Feedback Vertex Set on subclasses of $\Gpoly$ including chordal and circular-arc graphs, and we discuss variants of independent domination problems.

cs.DS↗

arXiv2016

Automata networks for multi-party communication in the Naming Game

The Naming Game has been studied to explore the role of self-organization in the development and negotiation of linguistic conventions. In this paper, we define an automata networks approach to the Naming Game. Two problems are faced: (1) the definition of an automata networks for multi-party communicative interactions; and (2) the proof of convergence for three different orders in which the individuals are updated (updating schemes). Finally, computer simulations are explored in two-dimensional lattices with the purpose to recover the main features of the Naming Game and to describe the dynamics under different updating schemes.

cs.CL↗

arXiv2015

PSPACE-Completeness of Majority Automata Networks

We study the dynamics of majority automata networks when the vertices are updated according to a block sequential updating scheme. In particular, we show that the complexity of the problem of predicting an eventual state change in some vertex, given an initial configuration, is PSPACE-complete.

cs.DM↗

arXiv2014

Algorithms parameterized by vertex cover and modular width, through potential maximal cliques

In this paper we give upper bounds on the number of minimal separators and potential maximal cliques of graphs w.r.t. two graph parameters, namely vertex cover ($\operatorname{vc}$) and modular width ($\operatorname{mw}$). We prove that for any graph, the number of minimal separators is $\mathcal{O}^*(3^{\operatorname{vc}})$ and $\mathcal{O}^*(1.6181^{\operatorname{mw}})$, and the number of potential maximal cliques is $\mathcal{O}^*(4^{\operatorname{vc}})$ and $\mathcal{O}^*(1.7347^{\operatorname{mw}})$, and these objects can be listed within the same running times. (The $\mathcal{O}^*$ notation suppresses polynomial factors in the size of the input.) Combined with known results, we deduce that a large family of problems, e.g., Treewidth, Minimum Fill-in, Longest Induced Path, Feedback vertex set and many others, can be solved in time $\mathcal{O}^*(4^{\operatorname{vc}})$ or $\mathcal{O}^*(1.7347^{\operatorname{mw}})$.

cs.DS↗