ArticleOriginal scientific text

Title

Category theorems concerning Z-density continuous functions

Authors 1, 2

Affiliations

  1. Department of Mathematics, West Virginia University, Morgantown, West Virginia 26506, U.S.A.
  2. Department of Mathematics, University of Louisville, Louisville, Kentucky 40292, U.S.A.

Abstract

The ℑ-density topology T on ℝ is a refinement of the natural topology. It is a category analogue of the density topology [9, 10]. This paper is concerned with ℑ-density continuous functions, i.e., the real functions that are continuous when the ℑ-density} topology is used on the domain and the range. It is shown that the family C of ordinary continuous functions f: [0,1]→ℝ which have at least one point of ℑ-density continuity is a first category subset of C([0,1])= {f: [0,1]→ℝ: f is continuous} equipped with the uniform norm. It is also proved that the class C of ℑ-density continuous functions, equipped with the topology of uniform convergence, is of first category in itself. These results remain true when the ℑ-density topology is replaced by the deep ℑ-density topology.

Keywords

ℑ-density topology, ℑ-density continuous functions, first category sets

Bibliography

  1. A. M. Bruckner, Differentiation of Real Functions, Lecture Notes in Math. 659, Springer, 1978.
  2. K. Ciesielski and L. Larson, Analytic functions are ℑ-density continuous, submitted.
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  5. K. Ciesielski and L. Larson, Various continuities with the density, ℑ-density and ordinary topologies on ℝ, Real Anal. Exchange, to appear.
  6. K. Ciesielski, L. Larson and K. Ostaszewski, Density continuity versus continuity, Forum Math. 2 (1990), 265-275.
  7. E. Łazarow, The coarsest topology for I-approximately continuous functions, Comment. Math. Univ. Carolin. 27 (4) (1986), 695-704.
  8. R. J. O'Malley, Baire*1, Darboux functions, Proc. Amer. Math. Soc. 60 (1976), 187-192.
  9. W. Poreda, E. Wagner-Bojakowska and W. Wilczyński, A category analogue of the density topology, Fund. Math. 125 (1985), 167-173.
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Additional information

http://matwbn.icm.edu.pl/ksiazki/fm/fm140/fm14017.pdf

Pages:
79-85
Main language of publication
English
Received
1991-02-11
Published
1991
Exact and natural sciences