Browsing by Author "Balcázar Navarro, José Luis"
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Computational power of neural networks: a Kolmogorov complexity characterization
Balcázar Navarro, José Luis; Gavaldà Mestre, Ricard; Siegelmann, H. (19930101)
External research report
Open AccessThe computational power of neural networks depends on properties of the real numbers used as weights. We focus on networks restricted to compute in polynomial time, operating on boolean inputs. Previous work has demonstrated ... 
Connections among non uniform models for problems requiring high amount of resources
Balcázar Navarro, José Luis; Gabarró Vallès, Joaquim (198511)
External research report
Open AccessWe characterize in terms of oracle Turing machines the classes defined by exponential lower bounds on some nonuniform complexity measures. After, we use the same methods to give a new characterization of classes defined ... 
De cómo ciertos conjuntos no pueden ser NPcompletos
Balcázar Navarro, José Luis (Universitat Politècnica de Barcelona. Centre de Càlcul, 198209)
Article
Open AccessEn este artículo se presenta una visión general a los últimos resultados acontecidos en el área de la estructura de la clase NPcompleta y su relación con el problema de si: P=NP o P diferente de NP. 
Deciding bisimilarity is Pcomplete
Balcázar Navarro, José Luis; Gabarró Vallès, Joaquim; Santha, Miklos (1990)
External research report
Open AccessOn finite labelled transition systems, the problems of deciding strong bisimilarity, observation equivalence, and observation congruence are Pcomplete under manyone NCreducibility. As a consequence, algorithms for ... 
Deriving specifications of embeddings in recursive program design
Roselló Balanyà, Celestí; Balcázar Navarro, José Luis; Peña Marí, Ricardo (1989)
External research report
Open AccessThe design of recursive functions is a wellstudied subject. Design methods require a specification to start with, however, when an embedding design is attempted at, it is not clear how the specification of the embedding ... 
Diameter minimization in networks for SIMD machines
Beivide Palacio, Ramon; Balcázar Navarro, José Luis (1985)
External research report
Open AccessWe propose an algebraic constructive method which allows to find a certain kind of networks having optimal diameter. These interconnection networks have been proposed for SIMD machines. We compare the results with other ... 
El algoritmo de compleción de KnuthBendix
Balcázar Navarro, José Luis (1988)
External research report
Open AccessAn introduction to the confluence and finite termination properties of rewriting systems is presented and also to the KunthBendix completion algorithm is presented. 
Embedding: a unifying concept for recursive program design
Roselló Balanyà, Celestí; Balcázar Navarro, José Luis; Peña Marí, Ricardo (1988)
External research report
Open AccessThe concept of embedding one function into another is used to get a unified view of some wellknown design techniques, such as loop derivation using inveriants, recursion removal, or foldingunfolding. A design method for ... 
Empirical results on longlived renaming algorithms
Moral Boadas, Sandra; Balcázar Navarro, José Luis (199709)
External research report
Open AccessThe Longlived Renaming problem is an important subject in Distributed Algorithms. The Renaming problem consists in providing processes with new names from a hopefully smaller name space. In the longlived version, only ... 
Entailment among probabilistic implications
Atserias, Albert; Balcázar Navarro, José Luis (Institute of Electrical and Electronics Engineers (IEEE), 2015)
Conference report
Open AccessWe study a natural variant of the implicational fragment of propositional logic. Its formulas are pairs of conjunctions of positive literals, related together by an implicationallike connective, the semantics of this sort ... 
Examples of CFbiinmune and CFlevelable sets in LOGSPACE
Balcázar Navarro, José Luis; Díaz Cort, Josep; Gabarró Vallès, Joaquim (1984)
External research report
Open AccessWe find sets in the class LOGSPACE (online) that do not have good respectively approximations by contextfree languages. For that we introduce the languages CFbiinmune and CFlevelable. We prove the results by defining ... 
Frequent sets, sequences, and taxonomies: new, efficient algorithmic proposals
Baixeries i Juvillà, Jaume; Casas Garriga, Gemma; Balcázar Navarro, José Luis (200012)
External research report
Open AccessWe describe efficient algorithmic proposals to approach three fundamental problems in data mining: association rules, episodes in sequences, and generalized association rules over hierarchical taxonomies. The association ... 
Functional oracle queries as a measure of parallel time
Álvarez Faura, M. del Carme; Balcázar Navarro, José Luis; Jenner Núñez, Birgit (199008)
External research report
Open AccessWe discuss two notions of functional oracle for logarithmic spacebounded machines, which differ in whether there is only one oracle tape for both the query and the answer or a separate tape for the answer, which can still ... 
Generalized Kolmogorov complexity in relativized separations
Gavaldà Mestre, Ricard; Torenvliet, Leen; Watanabe, Osamu; Balcázar Navarro, José Luis (199004)
External research report
Open AccessWe describe several developments of a technique, due to Hartmanis, that uses Kolmogorov complexity to prove the existence of relativizations separating complexity classes. The main advantage of these proofs is that they ... 
Global optimality in kmeans clustering
Tîrnauca, Cristina; Gómez Pérez, Domingo; Balcázar Navarro, José Luis; Montaña Arnaiz, José Luis (20180501)
Article
Open AccessWe study the problem of finding an optimum clustering, a problem known to be NPhard. Existing literature contains algorithms running in time proportional to the number of points raised to a power that depends on the ... 
Horn axiomatizations for sequential data
Balcázar Navarro, José Luis; Casas Garriga, Gemma (200509)
External research report
Open AccessWe propose a notion of deterministic association rules for ordered data. We prove that our proposed rules can be formally justified by a purely logical characterization, namely, a natural notion of empirical Horn approximation ... 
Immunity and simplicity in relativizations of probabilistic complexity classes
Balcázar Navarro, José Luis; Russo, David A. (198805)
Article
Open AccessThe existence of immune and simple sets in relativizations of the probabilistic polynomial time bounded classes is studied. Some techniques previously used to show similar results for relativizations of P and NP are adapted ... 
Iteratorbased algorithms in selftuning discovery of partial implications
Balcázar Navarro, José Luis; García Sáiz, Diego; de la Dehesa, Javier (CEUR Workshop Proceedings, 2012)
Conference report
Open AccessWe describe the internal algorithmics of our recent implementation of a closurebased selftuning associator: yacaree. This system is designed so as not to request the user to specify any threshold. In order to avoid the ... 
Learnability of Kolmogoroveasy circuit expressions via queries
Balcázar Navarro, José Luis; Buhrman, H; Hermo, M (199502)
External research report
Open AccessCircuit expressions were introduced to provide a natural link between Computational Learning and certain aspects of Structural Complexity. Upper and lower bounds on the learnability of circuit expressions are known. We ... 
Learning definite Horn formulas from closure queries
Arias Vicente, Marta; Balcázar Navarro, José Luis; Tîrnauca, Cristina (20170107)
Article
Open AccessA definite Horn theory is a set of ndimensional Boolean vectors whose characteristic function is expressible as a definite Horn formula, that is, as conjunction of definite Horn clauses. The class of definite Horn theories ...