Á. Császár

Eötvös Loránd University, Budapeŝto, Budapest, Hungary

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Publications (49)17.83 Total impact

  • Ákos Császár
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    ABSTRACT: We define weak structures and show that these structures can replace in many situations generalized topologies or minimal structures.
    Acta Mathematica Hungarica 01/2011; 131(1):193-195. · 0.35 Impact Factor
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    Á. Császár, E. Makai Jr
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    ABSTRACT: In generalizing constructions of N.V. Veličko, the paper starts from two generalized topologies µ and µ′ on a set X and introduces two more generalized topologies gd(µ, µ′) and δ(µ,µ′) with the examination of their properties.
    Acta Mathematica Hungarica 05/2009; 123(3). · 0.35 Impact Factor
  • Á. Császár
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    ABSTRACT: The definition of the product of topologies is generalized in such a way that topologies are replaced by generalized topologies in the sense of [3].
    Acta Mathematica Hungarica 01/2009; 123(1):127-132. · 0.35 Impact Factor
  • Á. Császár
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    ABSTRACT: As generalization of the construction of I-τ where τ is a topology and I is an ideal [11], and similarly of $$ \mathcal{H} $$-µ where µ is a generalized topology and $$ \mathcal{H} $$ is a hereditary class [5], we introduce generalized topologies starting from two generalized topologies µ and µ′.
    Acta Mathematica Hungarica 01/2009; 122(1):153-159. · 0.35 Impact Factor
  • Á. Császár
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    ABSTRACT: It is shown in the paper [1] that every generalized topology can be generated by a generalized neighbourhood system. Following the paper [3], we discuss some questions related to this construction.
    Acta Mathematica Hungarica 12/2008; 121(4). · 0.35 Impact Factor
  • Á. Császár
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    ABSTRACT: The paper discusses the generalization of a construction described in [6] for the case when the starting point topology is replaced by a generalized topology.
    Acta Mathematica Hungarica 09/2008; 120(4):351-354. · 0.35 Impact Factor
  • Á. Császár
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    ABSTRACT: It is shown that the theory of δ-and θ-modifications of topological spaces (see [3]) can be generalized for the case when the topology is replaced by a generalized topology in the sense of [1].
    Acta Mathematica Hungarica 07/2008; 120(3):275-279. · 0.35 Impact Factor
  • Á. Császár
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    ABSTRACT: A quasi-topology is a generalized topology (cf. [3]) closed for finite intersections. The paper discusses the question whether statements valid for topologies can be generalized for quasi-topologies.
    Acta Mathematica Hungarica 01/2008; 119(1):197-200. · 0.35 Impact Factor
  • Á. Császár
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    ABSTRACT: The purpose of the paper is to show that the construction leading from a topology and an ideal of sets to another topology remains valid, together with a lot of applications, if topology is replaced by generalized topology and ideal by hereditary class.
    Acta Mathematica Hungarica 03/2007; 115(1):29-36. · 0.35 Impact Factor
  • Á. Császár
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    ABSTRACT: The concept of normality is defined for generalized topologies in the sense of [1], a few properties of normal spaces are proved, and their characterization with the help of a suitable form of Urysohn’s lemma is discussed.
    Acta Mathematica Hungarica 01/2007; 115(4):309-313. · 0.35 Impact Factor
  • Ákos Császár
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    ABSTRACT: Summary There is a formula for the interior of a set in a generalized topology composed of the γ-open sets, where γ is a monotonic map in the power set of X. There are known conditions for a γ assuring that this formula is valid. The paper gives essential generalizations for these conditions and contains some applications.
    Acta Mathematica Hungarica 01/2006; 113(4):325-332. · 0.35 Impact Factor
  • Ákos Császár
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    ABSTRACT: It is proved a rather general version of the statement that if the union of arbitrary elements of a system λ always belongs to λ then the intersections of elements of λ constitute an ultratopology (i.e. a topology where intersections of open sets are open).
    Acta Mathematica Hungarica 12/2005; 110(1):153-157. · 0.35 Impact Factor
  • Ákos Császár
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    ABSTRACT: Summary In the paper [5], several operations on generalized topologies are considered. They are not monotone in general, but an old result on monotonicity may be sharpened.
    Acta Mathematica Hungarica 08/2005; 108(4):351-354. · 0.35 Impact Factor
  • Ákos Császár
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    ABSTRACT: Summary We study the even power means of a sum analogous to Dedekind sums, and give a sharp asymptotic formula.
    Acta Mathematica Hungarica 01/2005; 106(1):53-66. · 0.35 Impact Factor
  • Ákos Császár
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    ABSTRACT: The fundamental concepts in topological spaces, in particular separation axioms, are presented in a manner that open sets are replaced by more general ones.
    Acta Mathematica Hungarica 06/2004; 104(1):63-69. · 0.35 Impact Factor
  • Ákos Császár
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    ABSTRACT: The investigations in [3] are made more precise by considering not only separation axioms for topological spaces but also those connected with Čech closures.
    Acta Mathematica Hungarica 01/2004; 102(3):249-260. · 0.35 Impact Factor
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    Ákos Császár
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    ABSTRACT: The paper presents a formula for the γ-interior of a set under special conditions for γ:expX→expX, more general than those in the previous paper [Acta Math. Hungar. 80 (1998) 89–93]. There are also some applications.
    Journal of Mathematical Analysis and Applications 01/2004; 297(2):490-494. · 1.05 Impact Factor
  • Ákos Császár
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    ABSTRACT: The author examines separation properties of the modification () of a topology connected with the concept of -cluster points in the sense of N. V. Veliko.
    Acta Mathematica Hungarica 12/2003; 102(1):151-158. · 0.35 Impact Factor
  • Á. Császár
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    ABSTRACT: It is shown that the concept of a connected set and the essential properties of connected sets can be generalized in the manner that the role of open sets is given to γ-open sets, where γ is a monotonic mapping of the power set.
    Acta Mathematica Hungarica 01/2003; 101(4):273-279. · 0.35 Impact Factor
  • Á. Császár
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    ABSTRACT: As it is well-known, a structure C belonging to one of the subcategories of MER, induces another structure C' belonging to another subcategory. The purpose of the paper is to investigate those C' that can be induced by a single C.
    Acta Mathematica Hungarica 01/2003; 99(4):305-314. · 0.35 Impact Factor

Publication Stats

452 Citations
17.83 Total Impact Points

Institutions

  • 1994–2011
    • Eötvös Loránd University
      • Department of Analysis
      Budapeŝto, Budapest, Hungary