I'm a mathematician at UNAM in Mexico City. I work in algebraic topology, homotopy theory and higher category theory, but am interested in all sorts of math.
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2026-08-19T16:14:17Z Event JSON
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Last Notes npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín Oh, it turns out the person wrote the code: "the LLM did not write any code, it updated the README and copy-pasted my code then added whitespace, comments, and function documentation". That changes the situation, right? I can review this like any other human-written PR? npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín Ooh, got my first LLM-co"authored" pull request! Luckily, I think I can just turn it down saying GNU Emacs cannot take that contribution without getting into a personal discussion. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…muy0 @nprofile…l2h8 I think the user wanted a manifesto promising you will maintain the status quo, which is the funniest use of the word "manifesto" I can recall. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…g0ws As the philosopher Neil Peart wrote: npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…l2h8 I think "more staff" is a very optimistic Freudian slip, and you actually meant "more stuff". :( npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín Man, LLMs really drive home the lesson that people differ *greatly* in how much the care whether the statements they make are accurate. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…d0jr Here on Mastodon the video did not appear. It did in the RSS feed for your blog: npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…4xpq @nprofile…g2n5 @nprofile…a6hr I think both things are true: politics in the US are heavily polarized between Democrats and Republicans, but also neither of them is leftist: the Democrats are centrists and the Republicans are far right. Occasional leftist politicians run as Democrats, not because that party is left-leaning, but because in that country there is only one other party and it is a far right one. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín I implemented org-babel support for 3 array languages I like a lot: Goal¹, BQN² and growler/k³. These languages are great for data munging so I find it very handy to use them in #OrgMode to process data stored in org tables. You can grab my implementations from my Emacs configuration at: npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…tfwq hahaha, yes probably! npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…tfwq Wow. Thanks for checking —it's something I didn't want to do on my phone. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín Why is LaTeX rendering on arXiv abstracts so slow? Are they still using MathJax 2.0? npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…4hp5 @nprofile…t6k2 After reading what your wife thought, I took a look at some reviews and it gave me flashbacks of reading my student evaluations: one review sides with your wife on the need for editing, calling it "a tedious, bloated epic"; another review calls it "tightly constructed". When I taught undergrads in the US, I remember getting student evaluations, from the same class, one which said I was "the best math teacher I've ever had" and one which said "I don't know how the university lets him teach". npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…pfuj I do 2x, except for certain accents which force me down to 1.5x. One thing I've noticed is that for complicated stuff, like a video of a math reseach seminar, listening at 2x forces me to pay attention whereas at 1x I often get distracted and have to rewind a bit. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…xuzd "blog first, then meet" sounds like such a good idea. Have you been doing it long? How do others take to it? How well does it work? npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…xuzd I won't use it all until I can submit to journals in Typst. Why learn a second document language similar to LaTeX when I don't need to? I learn programming languages for fun, not document markup languages (I guess Typst is both... maybe I should do Advent of Code in Typst —but definitely not mathematical documents until journals stop requiring LaTeX source.) npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…xuzd Wow, I didn't know metadata with that effect could even be crafted. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín What's up with people trying to convince me to use Typst? Do they think I like LaTeX? I use it because that's what the journals ask for! If journals accepted Typst source files, I'd give it a shot. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…xuzd I'd call it "conversion", in fact I think a lot of people already use that word when explaining what either "coercion" or "casting" mean. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…6pyy I found the author of that brilliant meme! It's Davide Castelvecchi, using a meme format devised by mathstodon don, @nprofile…tfwq! See this blog post for other nice fake math books: https://aperiodical.com/2022/05/didnt-graduate-texts-in-mathematics/ npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…6pyy npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…a3ey Did you the French Mathematical Society had decided not to attend the ICM? https://smf.emath.fr/actualites-smf/icm-2026-motion-du-ca npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…xuzd Thanks for explaining that. It does sound very cool. I think the workflow you mentioned is something that I've avoided in git because the few times I've tried it, it seemed like a hassle. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…xuzd I imagine you were using git before. What makes Jujutsu so much more convenient? npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín There is much truth to this post about about #math textbooks. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…g0zc "Random find of the day". "Random"? I see what you did there! npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…t6k2 Let's move on to something where we don't agree, then. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín Great line I just heard an interviewer say: "Can we move on to some area where we don't completely agree?" npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…q443 Colby is another decent type of cheese originating in the US. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…4hp5 Maybe that's the key! Maybe the methodology is that you compute some global "humanities score" for each university and then "normalize" by dividing by the number of humanities departments. 😛 npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…4hp5 npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…q443 npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…4hp5 npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín I was so naive: I thought that once I passed my qualifying exams I'd never feel stressed by qualifying exams ever again! I failed to take into account I'd one day have graduate students, like them and empathize with them. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…a3ey I misunderstood, I thought the errata were missing, but only part of them are. Sorry for unnecessary comment. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…a3ey This doesn't answer your question, but one of the errata was probably about a gap in his proof of the Jordan curve theorem I found. We wrote a short corrigendum explaining the gap and two ways to fill it in: https://webhomes.maths.ed.ac.uk/~v1ranick/jordan/brouwer-cor-fun.pdf npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…rrqe Not wanting reference documentation is complete unrelatable to me! My guess is that you either have a much better memory than I do, or are working with systems with bad reference documentation. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…8eua It's probably just a typo for "among us", the popular videogame that features characters that look like that shape. @nprofile…sn9y npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…w8t5 Not telling you the conclusion of their own work seems really weird to me! To a first approximation nobody cares what I do and nobody has read my papers (I'm hardly unique in this, of course), so I jump on any opportunity to tell people about my work. I would have expected others to feel the same way. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…rrqe Gotta chase those disambiguation clicks! (It actually works on me, I'm like: "I wonder what they meant".) npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…ztfm I think after 6 months it is always an acceptable time to ask about a paper. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…rrqe @nprofile…h3ed You're right Jon that automorphisms of P_G^abs are of the form mu(_, u), but the map r(u) = mu(_,u) is not a homomorphism G --> Aut(P_G^abs), because r(u) o r(v) = r(vu). You want r(u) = mu(_,u^{-1}) instead. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…8eua @nprofile…p3nn I wanted to say this, thanks for saving me the effort. (Except I would have said "we" since I only sound like an American.) npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…fhty I don't know, I kind of want the fields that use lambda to keep using it. It's a nice reminder that I'm leaving mainstream math and entering some adjacent land, like computer science or certain branches of logic,with their own language and customs. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…w8t5 This reminds me of the time I told a friend that even if you define functions as sets of pairs everyone thinks of them as "rules". He swore he actually thought of them as sets of pairs and I could get him to budge on that. But a couple of weeks later I caught him talking about the graph of a function and I said: "don't you mean the function?". npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…rrqe If I were your student I would ignore your distinction and think of it as part of the course material. I'd tell people "I learned this in Jon's course" without adding "of course, it was not part of the material". npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…rrqe As a counterpointal anecdote, as a student I always wanted to know what was true even if the proof was too advanced for me at the time. A course with a large percentage of unprovable-in-the-course claims would be frustrating, no doubt, but I always enjoyed a sprinkling of trailers for future math. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…u6hy I work at UNAM (Universidad Nacional Autónoma de México), but not at UNAM (University of Namibia). npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…fhty That's done with a nice Galois theory trick. Given an automorphism F of the field of complex numbers and a representation G --> GL(n,C) you get a new representation by applying F to all entries of the matrices. If you start with an irreducible representation the F-twisted one is also irreducible (because you could un-F-twist any decomposition). This means that automorphisms of C permute the rows of the character table, and this they fix the column sums. Therefore the column sums are rational numbers. But all entries of the table are algebraic integers; so the column sums are both rational numbers and algebraic integers, which makes them integers. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín Today I figured out a cute representation theory fact that must be well-known. The adjoint representation of a finite group G is a representation on the vector space C[G] but with the action given on the basis via g·x := gxg⁻¹. What's the decomposition of this representation into irreducibles? Well, the irreducible representation with character χ occurs with multiplicity given by the sum of the row of the character table corresponding to χ! I didn't even know before today that the row-sums of the character table were non-negative integers! npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…rrqe Is this why you were complaining about recurrence relations that mention n/2 in another post? npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…w8t5 I wasn't familiar with that Freyd quote! It makes me feel like I was on the right track when I wrote this in a survey on infinity-categories (section 2.4 of https://www.matem.unam.mx/~omar/papers/infinity-survey.pdf): npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…rrqe That's not a reason against naming things after people, since the problem of having multiple inequivalent definitions also happens to term that are not named after people. In fact, I would guess that problem happens a little less with things named after people. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…ztfm It tricked me into spending a few minutes looking at it. I stopped browsing when the definition of the chain complex used didn't make sense. https://mathstodon.xyz/@oantolin/115418057236389832 npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…2k3a Why did you decide to add Helm support? What does the Helm-specific interface do that the completing-read version doesn't do under Helm? npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…w8t5 For what it's worth, I don't find the nLab to be wrong often on topics I'm comfortable with. Wikipedia, of course is pretty good too, but there are many topics you can only find on nLab. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín Where does the r in American's pronunciation of Gödel (sounds like "girdle") come from? I can't remember right now if native English speakers from other countries do that too. Do they? npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…yu7x Beautiful! npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…59k6 I think I might hang out with too many constructivists on Mastodon. My first instinct was to correct you, to say you probably meant inhabited rather than non-empty, but... maybe not. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…6kk0 The first 3 of your 4 reasons proof assistants are interesting are some of the reasons I think mathematics (whether or not formalized) is interesting. Which I guess makes sense, but maybe I'm slightly disappointed your reasons aren't more specific to proof assistants. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…6kk0 I casually tried opening that link in Emacs's browser and learned Forester actually produces XML! And since you were complaining about the proposal to remove XSLT from the web platform a few days ago (from which I learned browsers come with XSLT!), my guess is that Forester is rendered by XSLT in my browser. That's pretty neat, but it means I need a browser with XSLT. Fortunately I can easily tell Emacs to always open your website in Firefox. 😛 npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…r9rs This reminded me of a story that Jon Bentley tells in More Programming Pearls (A very fun book!). npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…6kk0 I did not know about metaweblog, it's good there's a standard. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…6kk0 The feed reader I use, Inoreader, has labels (but calls them folders, which is probably not a bad idea: if you call them labels people will ask you to implement folders :D) and does deduplication. I haven't tested the deduplication function of Inoreader for two different reasons: (1) it's only for paid users and I am happy with the free version, (2) I never see duplicate posts in different feeds (I do see duplicate posts within a single feed sometimes, though). npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…pmdx I wonder if it'll be much smaller than usual because people are afraid to travel to the US. The Mathematical Congress of the Americas was held in Miami this month and some people told me that in some sessions close to half the speakers cancelled (I was one of the speaker who cancelled, so I had to ask a braver colleague who did go). npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…fa4k Arguably this stick insect is both! Also, they've changed illusive to elusive on the website already, I only see illusive in the link preview here on Mastodon. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…m4ns @nprofile…e9rt I'd say that while these are techincally under C-c and follow the letter of the law of the question, they don't really count because C-c <letter> is meant for user key bindings. If you had some C-c C-<letter> that would be spicier. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…6kk0 It's funny that happens in functorial semantics. I never hear people say that in other categories: "a set is just an inclusion from the empty set", "a group is just a homomorphism from the trivial group", "a vector space is just a linear transformation from the zero space". Those things are all true, of course, but nobody finds them useful. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…pmdx Then I got nothing. :) npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…v2av I don't understand: which field should have switched from using 1-category to what else? I have no guesses about which field you mean,but about what to switch to I would guess you mean 2-categories or (oo,1)-categories or (oo,oo)-categories. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…6kk0 Ouch. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…pmdx If people can think of an alternative section title that doesn't have formulas, rather than use that command you mentioned, I'd advise using the formula-less section title. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín You know how people advise you not to use mathematical formulas in section titles in LaTeX? Listen to them! npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…6kk0 Do you know how it did it? Maybe a weight inversely proportional to publication frequency? npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…6kk0 Oh, I see the comma and the truncated other feed name now. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…6kk0 I'm confused: how an I see that from the screenshot? npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…pmdx That would work, but it's almost the same length as "(n-1)-connected pi_n-finite" which had the advantage of not even requiring a definition! npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…pmdx I don't think that's too bad, you could certainly use that term, but it isn't what I would have guessed "virtually n-connected" meant: for spaces, I think of "virtually" as being related to finite covers, so I would have guessed that "virtually n-connected" meant the space is connected, pi_1 is finite and the universal cover is n-connected. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín It's a little odd to me that mathematicians use monads for their categories of algebras but functional programmers use them for their Kleisli categories. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…6cfc I didn't know that about the HoTT book but once I knew, I did immediately guess it must be Mike Shulman. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…hszg Well, ChatGPT is the poster boy for LLMs, so BC and AC would work, but to avoid confusion with COVID we could use L for LLM: BL and AL. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín I think I might edit my CV to add this next to the date I got my degree: "(5 years before the release of ChatGPT)". npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…fa4k It bothers me a little bit that it has both "National" and "of Athens" in the name. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín ChatGPT kept telling people this software had a certain feature that it didn't have, so the developers decided to implement it. Normally *people* use ChatGPT to vibe code, this is the first instance I'm aware of of *ChatGPT* using people to vibe code! npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…t9cc For visitors I think the main risk is the entry, not the subsequent visit if you are allowed to enter. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…hszg @nprofile…6kk0 I mean, examples of that are a dime a dozen. It is very common to have something like "Theorem. The following are equivalent: ...", and then "Definition. A thing satisfying any of those equivalent is called a ...", and then to use the definitions interchangeably. It's very very common in most fields of mathematics. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…yms8 I'll let @nprofile…hszg answer in more logic-style language, but the topologist's answer is as follows: you are right that both definitions involve data, in particular, the correct definition involves the section and retraction and the homotopies proving they are such; the difference is what happens in each case when you consider the space of all possible data. For the correct definition the space of such data is either empty (when f is not an equivalence) or contractible (when f is an equivalence). The contractibility means the data is "unique up to homotopy" in a strong sense, which is why one says it isn't extra data at all. For the wrong definition the space of data still indicates whether you have an equivalence of not: the space is empty when f is not an equivalence and is non-empty when it is. However when the space is non-empty it is not always contractible and can even have many connected components (that is why Martin says there emight be several different g: g's in different connected components of the space are what count as "genuinely" different). If you truncated the space of data for the wrong definition to just be either empty or contractible, then you get another correct definition (this truncation is called propositional truncation in HoTT and in traditional homotopy theory would be called the (-1)-st Postnikov section). npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…39xp Isn't it an LSP server? Ininagina that means no commands, you interact with it thought eglot or lsp-mode. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…yu7x Hahaha, I'm sorry, specially if I just cost you addition to heaven. 😅 npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…yu7x This gives new meaning and new higher stakes to the phrase "cinnamon challenge". npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…hszg For what it's worth, I tried this prompt with Gemini 2.5 flash: npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…68z0 @nprofile…6kk0 I must have been really lucky: I don't think I ever read anything that made dependent types sound mysterious. I can recommend the HoTT book for example, it's very easy to read for mathematicians. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…hszg Fair enough. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…hszg @nprofile…v2av I think caring about the difference is an artifact of the affordances in type theory where it is convenient to always treat the identity types as the preferred notion of isomorphism. In more traditional mathematics, you set up the category of your objects to have the kind of isomorphism you want to consider and then only use that notion of isomorphism between them (there are of course exceptions when you want to consider more than one notion of isomorphism between your objects, which is usually dealt with by setting up various categories and functors between them). npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…8atg Ah, so that's what it stands for! Obscure, frenCh progrAMming Language. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…hszg I does happen for me on the Mathstodon web page (Firefox on GNU/Linux), but my favorite Mastodon clients, the webclient phanpy.social and the Emacs package mastodon.el, don't preselect anything when replying. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…hszg How do you keep following the thread after you've been deleted? By manually going to the thread and checking every now and then to see if there's anything new? By hoping you catch new replies while browsing in your feed? Some people like being kept in the replies because the notifications help them stay in the loop. npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…6cfc You're right of course a out BG in general, but sometimes BG does have the homotopy of a graph. It happens if and only if G is free. @nprofile…v2av npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín @nprofile…6cfc I don't think homotopy theorists use the term "n-dimensional homotopy type" at all. There is the concept of "n-dimensional CW-complex" and therefore also the concept of "space with the homotopy type of an n-dimensional CW-complex". Maybe that's what @nprofile…v2av meant? As you point out Oscar, that is very different from being n-truncated (another term for n-type). npub17mjld0zpmqv8uam9grchpt02kmgdwxlj7m3ede9r5ueefcstpcwqfjrup0 Omar Antolín A student sent me the evaluation forms I need to fill out for him partially filled out. Again. I had to tell him the government wants *my* opinion of his academic performance, not his own opinion. Again. 😐
