Tag Archives: filters

Hoover’s maximal limit spaces II: products, liftings, retracts, function spaces, and hyperspaces

Posted on April 20, 2024 by jgl

Last time, we had introduced Hoover’s maximal limit spaces: spaces in which every convergent filter has a unique largest limit. That notion is closed under many constructions, as we will see: products, liftings, retracts, notably, and that is elementary. The … Continue reading →

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Hoover’s maximal limit spaces I: local strong sobriety, bounded sup-completeness and weak Hausdorffness

Posted on March 20, 2024 by jgl

In 1995, Douglas Hoover introduced and studied a notion of maximal limit spaces: spaces in which every convergent net has a unique largest limit. This has connections with many other kinds of spaces that we have explored already, and I … Continue reading →

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Weakly Hausdorff spaces, and locally strongly sober spaces

Posted on November 20, 2022 by jgl

A funny convergence of topics happened a few weeks ago. Frédéric Mynard told me about so-called locally strongly sober spaces (which, I am ashamed to say, I had heard about but completely forgotten about). At the same time, I was … Continue reading →

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Convergence without points

Posted on April 20, 2020 by jgl

Can you define convergence without mentioning points? More precisely, is there any form of Stone duality for convergence spaces, instead of just topological spaces? The short answer is yes. For the long answer, read the full post.

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The Rasiowa-Sikorski lemma and the Baire property

Posted on December 23, 2019 by jgl

Merry Christmas! And a Happy New Year, too. There are incredible links between logic and topology, and I would like to start with something called the Rasiowa-Sikorski lemma in logic. That is a theorem that states the existence of certain … Continue reading →

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