Opuscula Math. 34, no. 4 (2014), 777-788
http://dx.doi.org/10.7494/OpMath.2014.34.4.777
Opuscula Mathematica
On some subclasses of the family of Darboux Baire 1 functions
Gertruda Ivanova
Elżbieta Wagner-Bojakowska
Abstract. We introduce a subclass of the family of Darboux Baire 1 functions \(f:\mathbb{R}\rightarrow\mathbb{R}\) modifying the Darboux property analogously as it was done by Z. Grande in [On a subclass of the family of Darboux functions, Colloq. Math. 17 (2009), 95-104], and replacing approximate continuity with \(\mathcal{I}\)-approximate continuity, i.e. continuity with respect to the \(\mathcal{I}\)-density topology. We prove that the family of all Darboux quasi-continuous functions from the first Baire class is a strongly porous set in the space \(\mathcal{DB}_1\) of Darboux Baire 1 functions, equipped with the supremum metric.
Keywords: Darboux property, strong Świątkowski property, Baire property, \(\mathcal{I}\)-approximate continuity, quasi-continuity.
Mathematics Subject Classification: 26A15, 54C08.
- Gertruda Ivanova
- University of Łódź, Faculty of Mathematics and Computer Science, ul. Banacha 22, 90-238 Łódź, Poland
- Elżbieta Wagner-Bojakowska
- University of Łódź, Faculty of Mathematics and Computer Science, ul. Banacha 22, 90-238 Łódź, Poland
- Received: 2014-01-31.
- Revised: 2014-11-02.
- Accepted: 2014-11-17.