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We show that if a Hausdorff topological space satisfies one of the following properties:
a) has a countable, discrete dense subset and is hereditarily collectionwise Hausdorff;
b) has a discrete dense subset and admits a countable base;
then the existence of a (continuous) weak selection on implies weak orderability. As a special case of either item a) or b), we obtain the result for every separable metrizable space with a discrete dense subset.
Given a metric space ⟨X,ρ⟩, consider its hyperspace of closed sets CL(X) with the Wijsman topology . It is known that is metrizable if and only if X is separable, and it is an open question by Di Maio and Meccariello whether this is equivalent to being normal. We prove that if the weight of X is a regular uncountable cardinal and X is locally separable, then is not normal. We also solve some questions by Cao, Junnila and Moors regarding isolated points in Wijsman hyperspaces.
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