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arXiv · 1911.11461

Upper bounds for the tightness of the $G_\delta$-topology

Angelo Bella·Santi Spadaro
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Abstract

We prove that if $X$ is a regular space with no uncountable free sequences, then the tightness of its $G_\delta$ topology is at most continuum and if $X$ is in addition Lindel\"of then its $G_\delta$ topology contains no free sequences of length larger then the continuum. We also show that the higher cardinal generalization of our theorem does not hold, by constructing a regular space with no free sequences of length larger than $\omega_1$, but whose $G_\delta$ topology can have arbitrarily large tightness.

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Angelo Bella, Santi Spadaro. 2019-11-26. Upper bounds for the tightness of the $G_\delta$-topology. https://arxiv.org/abs/1911.11461

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