19 citations · 125 across the 36 of their papers we have counts for
Showing 2021Show all
3 papers · 1 filter
math.FA2021
Large Banach spaces with no infinite equilateral sets
Piotr Koszmider, Hugh Wark
A subset of a Banach space is called equilateral if the distances between any two of its distinct elements are the same. It is proved that there exist non-separable Banach spaces (…
math.FA2021
Banach spaces in which large subsets of spheres concentrate
Piotr Koszmider
We construct a nonseparable Banach space (actually, of density continuum) such that any uncountable subset of the unit sphere of contains unc…
math.FA2021
On coverings of Banach spaces and their subsets by hyperplanes
Damian Głodkowski, Piotr Koszmider
Given a Banach space we consider the -ideal of all of its subsets which are covered by countably many hyperplanes and investigate its standard cardinal characteristics as the ad…