p-points in iterated forcing extensions

Abstract

This is the published version, also available here: http://dx.doi.org/10.1090/S0002-9939-1978-0469759-X. First published in Proc. Amer. Math. Soc. in 1978, published by the American Mathematical Society.Selective ultrafilters exist in direct iterated ccc extensions whose length has uncountable cofinality, as do p-points which are not selective. Nonselective p-points also exist e.g. in an iterated Laver or Mathias extension of length w2 over a model of CH