An Excursion with Divergence Properties

Abstract

In this note, we compare and contrast various selective divergence properties such as the properties of being discretely selective and selectively highly divergent. We identify and incorporate a class of subsemigroups of the semigroup of strictly increasing maps from the naturals to themselves. We investigate certain implications for hyperspaces of finite subsets and characterize the closed discrete selection game on a space in terms of a particular selection game on the Vietoris hyperspace of finite subsets of that space. We also isolate some sufficient conditions on a space that guarantee that the corresponding Pixley-Roy hyperspace of finite subsets is discretely selective. We end by noting that the properties of being discretely selective and of being selectively highly divergent are equivalent in rings of continuous functions with standard topologies of uniform convergence.