ON THE COMPLETION OF NEARNESS FRAMES

Abstract

Several questions naturally arising from the unique existence of the completion of a nearness frame are investigated. In particular, the classical result that completion is a coreflection for uniform frames is extended to a substantially larger class of nearness frames but at the same time shown not to hold in general, and an analogue of this is established for the mere functoriality of the completion. Further, a natural variant of the notion of completion is studied, leading among other things to a completely new coreflection result.