Tomek Bartoszynski. On the structure of measurable filters on a countable set. Real analysis exchange, vol. 17 no. 2 (1992), pp. 681–701. - Tomek Bartoszynski and Saharon Shelah. Intersection of < 2ℵ0 ultrafilters may have measure zero. Archive for mathematical logic, vol. 31 (1992), pp. 221–226. - Tomek Bartoszynski and Haim Judah. Measure and Category—filters on ω. Set theory of

Abstract

Tomek Bartoszynski. On the structure of measurable filters on a countable set. Real analysis exchange, vol. 17 no. 2 (1992), pp. 681–701. - Tomek Bartoszynski and Saharon Shelah. Intersection of < 2ℵ0 ultrafilters may have measure zero. Archive for mathematical logic, vol. 31 (1992), pp. 221–226. - Tomek Bartoszynski and Haim Judah. Measure and Category—filters on ω. Set theory of