The Journal of Symbolic Logic

Research Article

A characterization of 2-square Ultrafilters

Ned I. Rosen

Boston College, Chestnut Hill, Massachusetts 02167

Abstract

The class of 2-square ultrafilters on ω equals the union, for n ≥ 1, of the classes of strictly n Ramsey ultrafilters on ω.

(Received April 15 1981)