Angelo Bella

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20142024

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math.GN2024

Strongly discrete subsets with Lindelöf closures

Angelo Bella, Santi Spadaro

We define a topological space to be an "SDL space" if the closure of each one of its strongly discrete subsets is Lindelöf. After distinguishing this property from the Lindelöf pro…

math.GN2023

On two questions on selectively highly divergent spaces

Angelo Bella, Santi Spadaro

A topological space $X$ is selectively highly divergent (SHD) if for every sequence of non-empty open subsets ${U_{n} : n \in ω}$ of $X$ , we can pick a point $x_{n} \in U_{n}$ , for every…

math.GN2016

On cardinality bounds involving the weak Lindelöf degree

Angelo Bella, Nathan Carlson

We give a general closing-off argument in Theorem 2.1 from which several corollaries follow, including (1) if $X$ is a locally compact Hausdorff space then $∣ X ∣ \leq 2^{w L (X) ψ (X)}$ ,…

math.GN2014

When is a space Menger at infinity?

Leandro F. Aurichi, Angelo Bella

We try to characterize those Tychonoff spaces $X$ such that $β X ∖ X$ has the Menger property.