Limit of an ultrafilter. #
- Ultrafilter.lim f: a limit of an ultrafilter- f, defined as the limit of- (f : Filter X)with a proof of- Nonempty Xdeduced from existence of an ultrafilter on- X.
If F is an ultrafilter, then Filter.Ultrafilter.lim F is a limit of the filter, if it exists.
Note that dot notation F.lim can be used for F : Filter.Ultrafilter X.