Formerly u/CanadaPlus101 on Reddit.

  • 2 Posts
  • 616 Comments
Joined 3 years ago
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Cake day: June 12th, 2023

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  • Sure, they’re okay. Honestly we might be a bit too strict about avoiding them, at this point.

    Where it becomes a problem is if you’d like to join whatever group, but the only one available is not open to you. Which happened a lot historically, but is rarer now.

    I think their claim is nonsense, grossly exaggerated at best.

    Can confirm, in my experience the problem with mancaves is that you pretty quickly want to let women in. There’s no tradeoff, we can not talk about our feelings and make a mess in a mixed gender crowd, too.














  • I mean, me neither. But if all sets are finite AoC just trivially holds, right? You can do it “manually”.

    If you back off to just ZF, parts of functional analysis will break. Linfinity space isn’t separable, and so isn’t necessarily Baire anymore, for example.

    If we go all the way to finitism or ultrafinitism it doesn’t really exist as a concept in the first place. But, whatever numerical engineering calculation will still work, and you can probably do something that looks like functional analysis to determine a mode of vibration, even if you’re actually just using a series of high-dimensional but finite spaces. Probably, anyway. Don’t ask me to prove it.



  • It wasn’t a mistake. Usually you’re talking about an infinite-dimensional TVS when you say Banach space - as in it’s just Banach, that’s the most you can say about it. I don’t mean R3.

    Stuff like the axiom of choice has a way of coming up in functional analysis. Sure, there’s weirder spaces, like from general topology or TVS theory in general, but Banach spaces are an example that are pretty widely used and studied. It seems like going with some pathological object I have to search around for would make the point less clear.

    The Banach-Tarski paradox wouldn’t work either without the AoC, but it’s just a specific counterexample, and Banach and Tarski’s careers will be fine since they both died decades ago.


  • Our current system? So ZFC?

    We move to a different, probably weaker system. Certain mathematicians studying hyper-infinite monstrosities like Banach spaces will be sad. Life will go on, though.

    Existing applied math should all work purely in the Von Neumann universe of finite sets, if you’re forced to go that far. Saying there’s actually an infinite number of points in a line is a kind of luxury; it’s just one that feels right to most mathematicians. A number that’s simply much larger than is worth bothering with can work the same way. In the same spirit, you can probably get rid of most of the Von Neumann universe without breaking practical things.

    If you mean actual practical math breaks, I dunno. In any reasonably complex inconsistent formal system, all statements can be proven true. Like 10 = 20. So, can I just grow more fingers somehow?

    Edit: Since this is Lemmy, it’s worth pointing out that Godel’s incompleteness theorem has a kind of interchangeability with the fact some questions are undecidable by Turing machine.

    Godel’s theorem has a kind of salacious, clickbait quality to it. Laymen will interpret all kinds of things into it. I’ve literally heard “so, math is useless then”. But, if you know algorithms, you know that saying they can’t determine if a loop ends is nowhere close to saying they’re going to stop working, or that they aren’t really good at what they can do.