Limit of an ultrafilter. #
Ultrafilter.lim f: a limit of an ultrafilterf, defined as the limit of(f : Filter X)with a proof ofNonempty Xdeduced from existence of an ultrafilter onX.
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.