P. Zakrzewski

activity

20172024

collaborators

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5 papers · 1 filter

math.LO2024

On two consequences of CH established by Sierpinski. II

Roman Pol, Piotr Zakrzewski

We continue a study of the relations between two consequences of the Continuum Hypothesis discovered by Waclaw Sierpinski, concerning uniform continuity of continuous functions and…

math.LO2023

On two consequences of CH established by Sierpiński

Roman Pol, Piotr Zakrzewski

We study the relations between two consequences of the Continuum Hypothesis discovered by Wacław Sierpiński, concerning uniform continuity of continuous functions and uniform conve…

math.LO2023

Countably perfectly meager and countably perfectly null sets

Tomasz Weiss, Piotr Zakrzewski

We study a strengthening of the notion of a universally meager set and its dual counterpart that strengthens the notion of a universally null set. We say that a subset $A$ of a per…

math.LO2020

Countably perfectly meager sets

Roman Pol, Piotr Zakrzewski

We study a strengthening of the notion of a perfectly meager set. We say that that a subset $A$ of a perfect Polish space $X$ is countably perfectly meager in $X$ , if for every seq…

math.LO2017

On Borel maps, calibrated $σ$ -ideals and homogeneity

Roman Pol, Piotr Zakrzewski

Let $μ$ be a Borel measure on a compactum $X$ . The main objects in this paper are $σ$ -ideals $I (d im)$ , $J_{0} (μ)$ , $J_{f} (μ)$ of Borel sets in $X$ that can be covered by countably many…

On two consequences of CH established by Sierpinski. II

On two consequences of CH established by Sierpiński

Countably perfectly meager and countably perfectly null sets

Countably perfectly meager sets

On Borel maps, calibrated σ-ideals and homogeneity

On Borel maps, calibrated $σ$ -ideals and homogeneity