Browsing by Author "Lozano Bojados, Antoni"
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A characterization of PFNP = PFNP[log]
Lozano Bojados, Antoni (199302)
Research report
Open AccessSome implications of the fact PFNP∥ = PFNP[log] are known in terms of equalities between complexity classes of sets, but a characterization in the same terms is still unknown. Here we provide a characterization in terms ... 
Antimagic labelings of caterpillars
Lozano Bojados, Antoni; Mora Giné, Mercè; Seara Ojea, Carlos (20190415)
Article
Open AccessA kantimagic labeling of a graph G is an injection from E(G) to {1,2, ..., E(G)+k} such that all vertex sums are pairwise distinct, where the vertex sum at vertex u is the sum of the labels assigned to edges incident ... 
Bounded queries to arbitrary sets
Lozano Bojados, Antoni (199109)
Research report
Open AccessWe prove that if P superA[k] = P superA[k+1] for some k and an arbitrary set A, then A is reducible to its complement under a relativized nondeterministic conjunctive reduction. This result shows the first known property ... 
Caterpillars are antimagic
Lozano Bojados, Antoni; Mora Giné, Mercè; Seara Ojea, Carlos; Tey Carrera, Joaquín (20210121)
Article
Open AccessAn antimagic labeling of a graph G is a bijection from the set of edges E(G) to {1,2,…,E(G)}, such that all vertex sums are pairwise distinct, where the vertex sum at vertex u is the sum of the labels assigned to the ... 
Caterpillars have antimagic orientations
Lozano Bojados, Antoni (20180101)
Article
Open AccessAn antimagic labeling of a directed graph D with m arcs is a bijection from the set of arcs of D to {1, . . . , m} such that all oriented vertex sums of vertices in D are pairwise distinct, where the oriented vertex sum ... 
Complejidad de problemas sobre representaciones sucintas de grafos
Lozano Bojados, Antoni (198805)
Research report
Open Access 
Distinguishing tournaments with small label classes
Lozano Bojados, Antoni (20190730)
Article
Open AccessA ddistinguishing vertex (arc) labeling of a digraph is a vertex (arc) labeling using d labels that is not preserved by any nontrivial automorphism. Let ρ(T) (ρ′(T)) be the minimum size of a label class in a 2distinguishing ... 
Els Límits de la computació : indecidibilitat i NPcompletesa
Serna Iglesias, María José; Álvarez Faura, M. del Carme; Cases Muñoz, Rafel; Lozano Bojados, Antoni (Edicions UPC, 2001)
Book
Restricted access to the UPC academic communityAquest text presenta una introducció a les teories de la calculabilitat i la complexitat a l'abast d'un estudiant de primer cicle d'una enginyeria informàtica. A partir de la justificació de la necessitat d'un model formal ... 
Fast calculation of entropy with Zhang's estimator
Lozano Bojados, Antoni; Casas Fernández, Bernardino; Bentz, Chris; Ferrer Cancho, Ramon (RAM  Verlag, 20161201)
Part of book or chapter of book
Restricted access  publisher's policyEntropy is a fundamental property of a repertoire. Here, we present an efficient algorithm to estimate the entropy of types with the help of Zhang’s estimator. The algorithm takes advantage of the fact that the number of ... 
Mining frequent closed rooted trees
Balcázar Navarro, José Luis; Bifet Figuerol, Albert Carles; Lozano Bojados, Antoni (201001)
Article
Open AccessMany knowledge representation mechanisms are based on treelike structures, thus symbolizing the fact that certain pieces of information are related in one sense or another. There exists a wellstudied process of closurebased ... 
On one query selfreducible sets
Lozano Bojados, Antoni; Ogiwara, Mitsunori (199101)
Research report
Open AccessWe study one worddecreasing selfreducible sets, which were introduced by Lozano and Torán. These are usual selfreducible sets with the peculiarity that the selfreducibility machine makes at most one query and this is ... 
On the complexity of moving vertices in a graph
Lozano Bojados, Antoni; Raghavan, Vijay (199801)
Research report
Open AccessWe consider the problem of deciding whether a given graph G has an automorphism which moves at least k vertices (where k is a function of V(G)), a question originally posed by Lubiw (1981). Here we show that this ... 
Relativized and positive separations of [delta sub 2 super p] and [fi sub 2 super p]
Lozano Bojados, Antoni; Torán Romero, Jacobo (1989)
Research report
Open Access 
Selfreducible sets of small density
Lozano Bojados, Antoni; Torán Romero, Jacobo (198911)
Research report
Open AccessWe study the complexity of sets that are at the same time selfreducible and sparse or mreducible to sparse sets. We show that sets of this kind are low for the complexity clases [delta sub 2 super p], [fi sub 2 super p], ... 
Succinct circuit representations and leaf languages are basically the same concept
Borchert, Bernd; Lozano Bojados, Antoni (199601)
Research report
Open AccessThis paper connects two topics of Complexity Theory: The topic of succinct circuit representations initiated by Galperin and Wigderson, and the topic of leaf languages. A Boolean circuit c describes in a natural way the ... 
Symmetry breaking in tournaments
Lozano Bojados, Antoni (2010)
Research report
Open AccessWe provide upper bounds for the determining number and the metric dimension of tournaments. A set of vertices S is a determining set for a tournament T if every nontrivial automorphism of T moves at least one vertex of S, ... 
Symmetry breaking in tournaments
Lozano Bojados, Antoni (20130324)
Article
Open AccessWe provide upper bounds for the determining number and the metric dimension of tournaments. A set of vertices S in V(T) is a determining set for a tournament T if every nontrivial automorphism of T moves at least one vertex ... 
The Complexity of modular graph automorphism
Arvind, V.; Beigel, Richard; Lozano Bojados, Antoni (199812)
Research report
Open AccessMotivated by the question of the relative complexities of the Graph Isomorphism and the Graph Automorphism problems, we define and study the modular graph automorphism problems. These are the decision problems mod_kGA ... 
Tilepacking tomography is NPhard
Chrobak, Marek; Dürr, Christoph; Guíñez, Flavio; Lozano Bojados, Antoni; Kim Thang, Nguyen (2010)
Conference report
Restricted access  publisher's policyDiscrete tomography deals with reconstructing finite spatial objects from their projections. The objects we study in this paper are called tilings or tilepackings, and they consist of a number of disjoint copies of a fixed ... 
Trees whose evendegree vertices induce a path are antimagic
Lozano Bojados, Antoni; Mora Giné, Mercè; Seara Ojea, Carlos; Tey Carrera, Joaquín (20190516)
Research report
Open AccessAn antimagic labeling of a connected graph G is a bijection from the set of edges E(G) to {1, 2, . . . , E(G)} such that all vertex sums are pairwise distinct, where the vertex sum at vertex v is the sum of the labels ...