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Weak topology on $\ell^2$ is an $\aleph_0$-space #761

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Moniker1998
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As the title.

In one of the articles $\aleph_0$-spaces on pi-base reference to https://topology.pi-base.org/properties/P000179/references that is $\aleph_0$-spaces by E. Michael, there's also contained a result that dual of a separable Banach space in its weak* topology is an $\aleph_0$-space, which shows $\ell^2$ in its weak topology is an $\aleph_0$-space.

#751

@Almanzoris
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Good result. I have just seen these PRs right now, it would have solved a few doubts I had about this space. Funnily enough, I have solved them earlier today, but deducing that it has a weaker property (Has a countable network), which would be your previous PR.

@Moniker1998
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Moniker1998 commented Sep 11, 2024

Yes. My primary goal was to obtain separation properties for this space, but then I've seen one could just prove it has countable network, i.e. it's a cosmic space (which follows from $\ell^2$ having countable network), and here we have an even stronger property that it has countable k-network.

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