Normality and Martin's axiom
We introduce the notion of a strongly Whyburn space, and show that a space is strongly Whyburn if and only if is Whyburn. We also show that if is Whyburn for any Whyburn space , then is discrete.
The following statement is proved to be independent from : Let be a Tychonoff space with and . Then a union of less than of nowhere dense subsets of is a union of not greater than of nowhere dense subsets.
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 .