Now showing items 1-20 of 78

    • A first-order isomorphism theorem 

      Allender, Eric; Balcázar Navarro, José Luis; Immerman, Neil (1992)
      Research report
      Open Access
      We show that for most complexity classes of interest, all sets complete under first-order projections are isomorphic under first-order isomorphisms. That is, a very restricted version of the Berman-Hartmanis Conjecture holds.
    • A lattice representation of relations, multivalued dependencies and Armstrong relations 

      Baixeries i Juvillà, Jaume; Balcázar Navarro, José Luis (2005)
      Conference report
      Restricted access - publisher's policy
      We present a lattice-base formalism to relate, in a novel way, different representation methods for relational data. Specifically, relations given extensionally by tuples, multivalued dependencies, and Armstrong relations ...
    • A lattice-based method for structural analysis 

      Casas Garriga, Gemma; Díaz López, Pablo; Balcázar Navarro, José Luis (2005-09)
      Research report
      Open Access
      In this paper we revisit the foundations of formal concept analysis for ordered contexts of [4]. From the theoretical point of view, the obtained lattice has proved to be a proper unifying framework for reasoning about ...
    • A New abstract combinatorial dimension for exact learning via queries 

      Balcázar Navarro, José Luis; Castro Rabal, Jorge; Guijarro Guillem, David (2000-02)
      Research report
      Open Access
      We introduce an abstract model of exact learning via queries that can be instantiated to all the query learning models currently in use, while being closer to them than previous unificatory attempts. We present a ...
    • A Note on genericity and bi-immunity 

      Balcázar Navarro, José Luis; Mayordomo, E (1994-11)
      Research report
      Open Access
      Generic sets have all properties (from among a suitably chosen class) that can be enforced by finite extension arguments. In particular, p-generic set are known to be P-bi-immune. We try to clarify the precise relationship ...
    • A note on the query complexity of learning DFA 

      Balcázar Navarro, José Luis; Díaz Cort, Josep; Gavaldà Mestre, Ricard; Watanabe, Osamu (1992)
      Research report
      Open Access
      It is known that the class of deterministic finite automata is polynomial time learnable by using membership and equivalence queries. We investigate -- the query complexity -- the number of membership and equivalence queries ...
    • A Transformation scheme for double recursion 

      Balcázar Navarro, José Luis (1994-02)
      Research report
      Open Access
      A tail recursive program (with a single recursive call per case) is derived from a generic recursive program with two independent recursive calls, under no algebraic hypothesis whatsoever. The iterative version, fully ...
    • Adaptive logspace and depth-bounded reducibilities 

      Balcázar Navarro, José Luis (1991-04)
      Research report
      Open Access
      We discuss a number of results regarding an important subject: the study of the computational power of depth-bounded reducibilities, their use to classify the complexity of computational problems, and their characterizations ...
    • Adaptive logspace reducibility and parallel time 

      Álvarez Faura, M. del Carme; Balcázar Navarro, José Luis; Jenner, Birgit (1991-11)
      Research report
      Open Access
      We discuss two notions of functional oracle for logarithmic space-bounded 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 ...
    • Algorithms for learning finite automata from queries: a unified view 

      Balcázar Navarro, José Luis; Díaz Cort, Josep; Gavaldà Mestre, Ricard; Watanabe, Osamu (1996-09)
      Research report
      Open Access
      In this survey we compare several known variants of the algorithm for learning deterministic finite automata via membership and equivalence queries. We believe that our presentation makes it easier to understand what ...
    • Algoritmos de distancias mínimas en grafos 

      Balcázar Navarro, José Luis (1986-05)
      Research report
      Open Access
    • An optimal parallel algorithm for learning DFA 

      Balcázar Navarro, José Luis; Díaz Cort, Josep; Gavaldà Mestre, Ricard; Watanabe, O. (Universitat Politècnica de Catalunya. Departament de Llenguatges i Sistemes Informàtics, 1993-01-01)
      Research report
      Open Access
      In 1987, D. Angluin presented an algorithm that exactly learns regular languages represented by deterministic finite automata (dfa) from Membership and Equivalence queries. Furthermore, the algorithm is feasible in the ...
    • Anàlisi d'un algorisme de multiplicació d'enters 

      Marco Gómez, Jordi; Balcázar Navarro, José Luis (1993-10)
      Research report
      Open Access
      Es proposa un algorisme de multiplicació d'enters basat en l'esquema "divideix i venç", però diferent del de Karatsuba i Ofman. Es fa l'anàlisi de la seva complexitat. Es troba que, encara que sembli millor que els ja ...
    • Apuntes sobre el cálculo de la eficiencia de los algoritmos 

      Balcázar Navarro, José Luis (1993-09)
      Research report
      Open Access
    • Border algorithms for computing Hasse diagrams of arbitrary lattices 

      Balcázar Navarro, José Luis; Tirnauca, Cristina (Springer, 2011)
      Conference report
      Restricted access - publisher's policy
      Lattices are mathematical structures with many applications in computer science; among these, we are interested in fields like data mining, machine learning, or knowledge discovery in databases. One well-established use ...
    • CALCULABILITAT (Examen 2n quadrim) 

      Balcázar Navarro, José Luis (Universitat Politècnica de Catalunya, 1998-06-10)
      Exam
      Restricted access to the UPC academic community
    • CALCULABILITAT (Examen 2n quadrim) 

      Balcázar Navarro, José Luis (Universitat Politècnica de Catalunya, 1999-06-10)
      Exam
      Restricted access to the UPC academic community
    • Canonical Horn representations and query learning 

      Arias Vicente, Marta; Balcázar Navarro, José Luis (2009-05)
      Research report
      Open Access
      We describe an alternative construction of an existing canonical representation for definite Horn theories, the emph{Guigues-Duquenne} basis (or GD basis), which minimizes a natural notion of implicational size. We extend ...
    • Characterization and Armstrong relations for Degenerated Multivalued Dependencies using Formal Concept Analysis 

      Baixeries i Juvillà, Jaume; Balcázar Navarro, José Luis (Springer, 2005)
      Conference report
      Restricted access - publisher's policy
      Functional dependencies, a notion originated in Relational Database Theory, are known to admit interesting characterizations in terms of Formal Concept Analysis. In database terms, two successive, natural extensions of ...
    • Characterizations of logarithmic advice complexity classes 

      Balcázar Navarro, José Luis; Hermo Huguet, Montserrat; Mayordomo, Elvira (1991-12-13)
      Research report
      Open Access
      The complexity classes P/log and Full-P/log, corresponding to the two standard forms of logarithmic advice for polynomial time, are studied. Characterizations are found in terms of Kolmogorov-simple circuits, bounded query ...