paper

Conglomerated filters, statistical measures, and representations by ultrafilters

arXiv:2012.02866

Abstract

Using a new concept of conglomerated filter we demonstrate in a purely combinatorial way that none of Erdös-Ulam filters or summable filters can be generated by a single statistical measure and consequently they cannot be represented as intersections of countable families of ulrafilters. Minimal families of ultrafilters and their intersections are studied and several open questions are discussed.