3 papers
math.CO2026
Augmentation Lemma for Halin Conjecture
Jerzy Wojciechowski
The longstanding conjecture of Halin characterizing the existence of normal spanning trees in infinite graphs has been recently proved by Max Pitz [3]. A critical step in the proof…
math.GN2021
When is a category of adherence-determined convergences simple?
Frédéric Mynard, Jerzy Wojciechowski
Abstract. We provide a characterization of classes of filters for which the full subcategory of formed…
math.GN2021
Three problems in convergence theory
Jerzy Wojciechowski
In this note it is proved that the class of paratopologies is simple and that under the assumption that the measurable cardinals form a proper class, the class of hypotopologies is…