Canonical partition relations and point character of -spaces
For every countable non-limit ordinal α we construct an α-dimensional Cantor ind-manifold, i.e., a compact metrizable space such that , and no closed subset L of with ind L less than the predecessor of α is a partition in . An α-dimensional Cantor Ind-manifold can be constructed similarly.
Following Preuss' general connectedness theory in topological categories, a connectedness concept for approach spaces is introduced, which unifies topological connectedness in the setting of topological spaces, and Cantor-connectedness in the setting of metric spaces.
In this paper we complete the characterization of those , and such that is limit of a sequence of obstacles where
We compare several conditions sufficient for maximal resolvability of topological spaces. We prove that a space is maximally resolvable provided that for a dense set and for each the -character of at is not greater than the dispersion character of . On the other hand, we show that this implication is not reversible even in the class of card-homogeneous spaces.
We prove that every compact space is a Čech-Stone compactification of a normal subspace of cardinality at most , and some facts about cardinal invariants of compact spaces.