O riešení niektorých nerozhodnutelných topologických problémov
We show that if has countable extent and has a zeroset diagonal then is submetrizable. We also make a couple of observations regarding spaces with a regular -diagonal.
A sufficient condition for the pseudo radiality of the product of two compact Hausdorff spaces is given.
A scadic space is a Hausdorff continuous image of a product of compact scattered spaces. We complete a theorem begun by G. Chertanov that will establish that for each scadic space X, χ(X) = w(X). A ξ-adic space is a Hausdorff continuous image of a product of compact ordinal spaces. We introduce an either-or chain condition called Property which we show is satisfied by all ξ-adic spaces. Whereas Property is productive, we show that a weaker (but more natural) Property is not productive. Polyadic...
If Martin’s Axiom is true and the continuum hypothesis is false, and X is a compact Radon measure space with a non-separable space, then there is a continuous surjection from X onto .
For every cardinal τ and every ordinal α, we construct a metrizable space and a strongly countable-dimensional compact space of weight τ such that , and each metrizable space X of weight τ such that D(X) ≤ α is homeomorphic to a subspace of and to a subspace of .