Fundamenta Informaticae - Volume 14, issue 3

Article Type: Other

DOI: 10.3233/FI-1991-14301

Citation: Fundamenta Informaticae, vol. 14, no. 3, pp. i-viii, 1991

Authors: Balanescu, Tudor | Gheorghe, Marian

Article Type: Research Article

Abstract: This paper investigates the class of regular languages which are pf(k) – parsable. It is shown that k induces an infinite hierarchy in the family of regular languages and that every regular language is a homomorphic image of a pf(O) -parsable language. A pumping lemma for pf – parsable languages is also provided.

Keywords: pf(k) – parsable languages, pumping lemma

DOI: 10.3233/FI-1991-14302

Citation: Fundamenta Informaticae, vol. 14, no. 3, pp. 283-286, 1991

Authors: Hoogeboom, Hendrik Jan | Rozenberg, Grzegorz

Article Type: Research Article

Abstract: An elementary net system is the basic system model of net theory. The state space of an elementary net system is formalized through the notion of the case graph, which is an edge-labeled graph with a distinguished initial node. The paper investigates syntactic, i.e., graph theoretic properties of case graphs of elementary net systems. In particular it studies the structure of isomorphisms between case graphs.

DOI: 10.3233/FI-1991-14303

Citation: Fundamenta Informaticae, vol. 14, no. 3, pp. 287-300, 1991

Authors: Stoeva, Stefka P.

Article Type: Research Article

Abstract: Knowledge bases in the form of fuzzy production systems with weighting coefficients, i.e. sets of weighted fuzzy rules, are studied. A software implementation of a rule-firing algorithm. based on Zadeh’s generalized modus ponens. is presented. The time complexity of the algorithm proposed is determined. Different types of parallelism in processing of fuzzy production systems are explored.

DOI: 10.3233/FI-1991-14304

Citation: Fundamenta Informaticae, vol. 14, no. 3, pp. 301-312, 1991

Authors: Barua, Rana

Article Type: Research Article

Abstract: The usual notions of acceptance of automata acting on infinite strings yield sets that are in very low Borel classes. In response to a question by Landweber, Wiśniewski introduced the notion of generalized automata that yield sets at any specified level of the Borel hierachy. Here we show that most of Wiśniewski’s results can be easily derieved (and generalized) using the theory of positive analytical operations and δ – s operations.

DOI: 10.3233/FI-1991-14305

Citation: Fundamenta Informaticae, vol. 14, no. 3, pp. 313-322, 1991

Authors: Baratella, Stefano

Article Type: Research Article

Abstract: Aim of this paper is to provide an alternative proof of consistency for the completion of a semi-strict program. Furthermore, we prove the continuity of the immediate consequence map associated to a locally call-consistent program with respect to any preinterpretation that is a model of the equality theory of its Clark’s completion.

DOI: 10.3233/FI-1991-14306

Citation: Fundamenta Informaticae, vol. 14, no. 3, pp. 323-337, 1991

Authors: Apt, Krzysztof R. | Blair, Howard A.

Article Type: Research Article

DOI: 10.3233/FI-1991-14307

Citation: Fundamenta Informaticae, vol. 14, no. 3, pp. 339-343, 1991

Authors: Kaminski, Michael

Article Type: Research Article

Abstract: An embedding of minimal sets for default theories into nonmonotonic and nonmonotonic ground logics based on S4 and S5 is presented.

DOI: 10.3233/FI-1991-14308

Citation: Fundamenta Informaticae, vol. 14, no. 3, pp. 345-353, 1991

Authors: Truszczynski, Mirosław

Article Type: Research Article

Abstract: In the paper we study a family of modal nonmonotonic logics closely related to the family of modal nonmonotonic logics proposed by McDermott and Doyle. For a modal logic S and a fixed collection of formulas X we introduce the notion of an (S , X )-expansion. We restrict to modal logics which have a complete Kripke semantics. We study the properties of (S , X )-expansions and show that in many respects they are analogous to the properties of S -expansions in nonmonotonic modal logics of McDermott and Doyle.

DOI: 10.3233/FI-1991-14309

Citation: Fundamenta Informaticae, vol. 14, no. 3, pp. 355-366, 1991

Authors: Jankowski, Andrzej | Michalewicz, Zbigniew

Article Type: Research Article

Abstract: A number of approaches have been taken to represent compound, structured values in relational databases. We review a few such approaches and discuss a new approach, in which every set is represented as a Boolean term. We show that this approach generalizes the other approaches, leading to more flexible representation. Boolean term representation seems to be appropriate in handling incomplete information: this approach generalizes some other approaches (e.g. null value mark, null variables, etc). We consider definitions of algebraic operations on such sets, like join, union, selection, etc. Moreover, we introduce a measure of computational complexity of these operations.

DOI: 10.3233/FI-1991-14310

Citation: Fundamenta Informaticae, vol. 14, no. 3, pp. 367-385, 1991