On relations approximated by continuous functions
A subset of a space is almost countably compact in if for every countable cover of by open subsets of , there exists a finite subfamily of such that . In this paper we investigate the relationship between almost countably compact spaces and relatively almost countably compact subsets, and also study various properties of relatively almost countably compact subsets.
A subspace of a space is almost Lindelöf (strongly almost Lindelöf) in if for every open cover of (of by open subsets of ), there exists a countable subset of such that . In this paper we investigate the relationships between relatively almost Lindelöf subset and relatively strongly almost Lindelöf subset by giving some examples, and also study various properties of relatively almost Lindelöf subsets and relatively strongly almost Lindelöf subsets.
J. C. Mathews and D. W. Curtis, [4], have introduced some structures which generalize structures of uniform types to the product of two sets, and they obtain a generalized version of Banach's contraction mapping theorem. In this note we prove that these structures are obtained from the usual analogues by means of a particular bijection; hence we do not have a meaningful generalization. For example, this bijection provides, from a result by A. S. Davies, [1], an analogue of Banach's well-known contraction...
We show, in particular, that every remote point of is a nonnormality point of if is a locally compact Lindelöf separable space without isolated points and .
It is proved that every uncountable -bounded group and every homogeneous space containing a convergent sequence are resolvable. We find some conditions for a topological group topology to be irresolvable and maximal.