𝕁onas 🐈🐘

https://mathstodon.xyz/@jonasfrey

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jonasfrey_at_mathstodon.xyz@momostr.pink

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nprofile1qqsxsesty0jzsdq92r07c7gqmefty4ajd54sve6ypdnaedxe4glg4csprpmhxue69uhhyetvv9ujumt0d4hhxarj9ecxjmntjn3avh

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relay.momostr.pink

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Last Notes

2026-08-28 15:33:42 UTC

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But isn't it overkill to have the colon *and* the period? In the blog version you don't have the period.
@npub1gat…s5kp @npub1vlc…mzqq [@bstacey](https://icosahedron.website/@bstacey )

2026-03-15 20:59:25 UTC

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There are two names just above the list of names in the "if you'd like to collaborate ..." part, and they're also the first two signatories. So i'd assume they're the originators.
@npub1nf4…nqe4 @npub1zz2…9mhx @npub18qp…f9dp

2025-12-14 22:34:06 UTC

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> the universe fits the profile of a white hole a lot better than of a black hole.
Yes, because of the singularity in the past ? But if there also was a singularity in the future then it could be a black hole ?

2025-12-14 22:13:09 UTC

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So it the picture wrong or am I misinterpreting it ? Maybe the Hubble radius dot is close to the "black hole line", but not quite on it ? Would a universe with a big-cruch singularity in the future (that people used to believe in) be a black hole ? Or does the line capture the correct notion of black hole only for not-too-large objects ? Or is it about universe vs observable universe ?
(I have watched the video and remember the discussion of white holes, but my understanding of all this is superficial)

2025-12-14 21:14:11 UTC

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on the other hand, the whole universe is a black hole! (The Hubble radius dot in the graphic)

2025-11-10 20:22:44 UTC

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Maybe the quunits corresponding to the first factor are non-trivial because of the missing "S" in front of U(1)? If it was SU(1) it would be trivial. Is this a reasonable way of thinking about it?

2025-10-08 11:02:28 UTC

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Could you tell us the name of the paper please?
@npub14a5…9fse

2025-09-22 15:12:41 UTC

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Are you sure that infinitary logic admits "infinitely many alternating qantifiers" ? The wikipedia page seems to suggest that you can have universal and existential quantifiers binding infinitely many variables, but I don't see any mention of infinite alteration.

2025-08-20 11:40:02 UTC

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the video of the talk is now here:
https://youtu.be/f-uSU4PBh_0?si=Ae_Mvm330KLKVjAw

2025-08-19 14:49:15 UTC

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I got the same value!
https://media.mathstodon.xyz/media_attachments/files/115/055/979/837/947/681/original/8db7e6ee98908655.png

2025-07-23 16:15:01 UTC

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do you happen to have notes of such a course? I have never learned these things and would appreciate a intuitive (rather than axiomatic) introduction.

2025-02-03 20:48:25 UTC

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ahh yes and there was talk about "mixed Tate motives", and about a conjecture about their relation to the cosmic Galois group. I think Leila Schneps asked some follow up questions on that.

2025-02-03 20:46:28 UTC

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yes there was definitely talk of a cosmic Galois group, but I didn't understand it ... maybe it was something like "physicists are not really working over C, but over C extended with constants"?

2025-02-03 20:42:43 UTC

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I went to the talk and I think it will appear on the youtube channel of the Archive Trust for Research [1] (it's in French). I'm afraid I can't give a summary, but here are some things that were mentioned:
* Connes-Kreimer Hopf algebra / renormalization / Birkhoff decomposition (though I don't know which one, the Wikipedia page on Birkhoff decomposition is a disambiguation page)
* the Galois group Gal(\bar{Q}/Q) acts on dessins d'enfants
* "constants" depend on the energy level (that sounds like what @npub1nf4…nqe4 wrote
here [2] about observed charge of an electron depending on energy level of measurement?)
* fields C_p and Scholze-tilting
* Krasner hyperfields
* classification of finite fields generalizes to classification of finite "semi-fields" (like semi-rings) : there is one finite semi-field which is not a field, and it's {0,1} with max as addition. Connes calls this "characteristic 1"
* this is apparently related to thermodynamics and the Legendre transform is the the same as Fourier transform in this setting
* also, Connes credits Scholze with the insight that the "Fargues Fontaine curve" should be viewed over F_1? (not sure if F_1 here is the same as the semi-field above)
* then there's the "topos of frequencies" whose points are "rank 1 subgroups of R", and which can be represented as semi-direct product of [0,\infty) with the multiplicative monoid of natural numbers? C. mentioned the arithmetic site in this context, but I'm not sure if that's representing the same topos, or only related?
[1] https://www.youtube.com/@archivetrustforresearch
[2] https://mathstodon.xyz/@johncarlosbaez/113744746209768522