We continue the study, started in [8], of generalised filters. Prime prefil
ters have played a central role in the theory of (Lowen) fuzzy uniform spac
es and Lowen discovered a characterisation of the set of all minimal prime
prefilters finer than a given prefilter in terms of ultrafilters. We define
the notion of a prime generalised filter and describe the set of all minim
al prime g-filters finer than a given g-filter in terms of ultrafilters. Th
e relationship between prime prefilters and prime g-filters is revealed. Th
e behaviour of the images and preimages of g-filters are investigated. (C)
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