Sobrification of partially ordered sets.
Arhangel’skii [Sci. Math. Jpn. 55 (2002), 153–201] defined notions of relative paracompactness in terms of locally finite open partial refinement and asked if one can generalize the notions above to the well known Michael’s criteria of paracompactness in [17] and [18]. In this paper, we consider some versions of relative paracompactness defined by locally finite (not necessarily open) partial refinement or locally finite closed partial refinement, and also consider closure-preserving cases, such...
We obtain some new properties of the class of KC-spaces, that is, those topological spaces in which compact sets are closed. The results are used to generalize theorems of Anderson [1] and Steiner and Steiner [12] concerning complementation in the lattice of -topologies on a set .
It will be shown that if in a family of sets there exists a strong sequence of the length then this family contains a subfamily consisting of pairwise disjoint sets. The method of strong sequences will be used for estimating the weight of regular spaces.
In previous papers, various notions of pre-Hausdorff, Hausdorff and regular objects at a point in a topological category were introduced and compared. The main objective of this paper is to characterize each of these notions of pre-Hausdorff, Hausdorff and regular objects locally in the category of proximity spaces. Furthermore, the relationships that arise among the various , , , structures at a point are investigated. Finally, we examine the relationships between the generalized separation...