Michał Popławski

collaborators

4 papers

math.GN2026

Topological size of the set of universal and ultrahomogeneous retractions on the Urysohn space

Judyta BÄ k, Joanna GarbuliÅska-WÄgrzyn, MichaÅ PopÅawski

In this paper, we investigate the set $U (U)$ of universal and ultrahomogeneous $1$ -Lipschitz retractions acting on the Urysohn space as the subspace of the space…

math.CA2026

Extending Theorems of Boros and Menzer

Marek Balcerzak, MichaÅ PopÅawski

We extend results of Boros and Menzer on the alternative equation $f (x) f (y) = 0$ for generalized polynomials $f$ , and their theorems on the conditional inequality $f (x) f (y) \geq 0$ for…

math.GN2024

All iterated function systems are Lipschitz up to an equivalent metric

MichaÅ PopÅawski

A finite family $F = {f_{1}, \dots, f_{n}}$ of continuous selfmaps of a given metric space $X$ is called an iterated function system (shortly IFS). In a case of contractive se…

math.GN2024

Characterizing Lipschitz images of injective metric spaces

Judyta BÄ k, Taras Banakh, Joanna GarbuliÅska-WÄgrzyn +2

A metric space $X$ is {\em injective} if every non-expanding map $f : B \to X$ defined on a subspace $B$ of a metric space $A$ can be extended to a non-expanding map $f ˉ : A \to X$ .…