Abstract: This will be a continuation of last week's talk in which I discussed the Tukey ordering of ultrafilters. This week, I'll talk about a species of ultrafilters defined in terms of preservation by forcing. This species, like last week's, also admits a combinatorial definition. The two combinatorial definitions have a very similar "flavor". I'll speculate about prospects for combining the two sorts of combinatorial definitions. Speaker(s): Andreas Blass (UM)