The Eternal Doorman

Category theorists, it seems, can't help but go up , making more concrete stuff that they have to find names for. They should learn about abstraction.  See  Why is Physics So Difficult?  and  David Jaz Maiers - Compositionality via 2-algebra .  See also  Richard Southwell and Norman Wildberger on the Future of Mathematics . Norman's box numbers are a multisubset of the set 1={∅} which, according to nlab is an isomorphism class in the over category Set/1, I think. See the three examples in the comma category on nlab  and  fundamental theorem of topos theory .  Richard Garner, Polynomial comonads and comodules Subscribe to  HoTTEST .  David Spivak's talk "Categories = polynomial comonads", a simple demonstration. This is great. It should give Norman Wildberger a whole lot of new ideas for stuff he can do with polynumbers! It was given in September 2020. Tom Leinster on a general notion of magnitude: I learned something interesting a...

Subscribe to  Max Stirner . Benji Metha on Jaynes and Probability as Logical Inference So if there's another scientist in his audience, he is going to have to consider the probability of the results of the successive coin flips as being dependent on some hypotheses. For example, the scientist flipping the coins may not be using a fair coin, he may be basing the results on a distribution he observes from the predictions of the audience, or he may be using some mixture of these based on another random process he has invented, say by using one method if he throws four, five or six on a die, and the fair coin if he throws a one, a two or a three. Or he may be adjusting those mixtures according to how many heads or tails he has thrown so far, or, ... the possibilities are endless. So the Bayesian has to make some assumptions. The difference between the Bayesian and the frequentist is that the Bayesian will always have some idea of what their priors are conditioned on. In this case, the ...

It's a story by Roald Dahl , written in 1954, but which, 70 years later, is starting to look somewhat prophetic, ... Pre-order Toby and Len's robot story at  https://tibees.com/ . Subscribe to Tibees . 

My comments : I think the thing with set theory is it makes mathematics into a jungle where the predators have big teeth and long claws you can't survive without some crazy skill at something. In the end it's better to just live somewhere else. Subscribe to Richard Southwell . Subscribe to Insights into Mathematics . See  Joel Hamkins interviewed on About Logic .

If I do a Google search for 2-Algebra then it says "Algebra 2 is the second math course typically taken in high school, building directly on the foundations of Algebra 1. It expands on linear equations, quadratics, and graphing, while introducing more advanced concepts like polynomial, exponential, logarithmic, and trigonometric functions." See (infinity,n)-module in nlab.  From the video description: Abstract: A complex system may be designed modularly by putting together interacting component subsystems. Since analyses of complex systems can often scale very poorly with their size, it pays to use the modular structure of such systems to divide the task of analysis across the component subsystems. Many analyses of systems may be encoded as homomorphism search problems between systems of the same sort. This suggests attending to categories of systems and their homomorphisms. In this talk, we'll consider the modular structure of a class of systems as a 2-algebra — an alge...

See Open letter in Support of Svetlana Mesyats where there is an address to send your support of a petition. Svetlana Mesyats is an internationally renowned Classicist specialising in Neoplatonism and the Aristotelian tradition in Late Antiquity. Since 1999 she has held the position of Senior Researcher at the Institute of Philosophy of the Russian Academy of Sciences in Moscow. On Tuesday, May 19, 2026, Svetlana was arrested on charges related to the alleged mismanagement of public funds allocated for the preparation of new Russian translations of Aristotle’s works. After spending two days in custody, she was placed under house arrest. The investigation into Svetlana’s case is ongoing and, given the charges, she could face up to 10 years in prison. Svetlana’s arrest occurred in the context of a long-standing struggle for control over the Institute. Svetlana, who has never held a senior administrative position in the Academy or elsewhere, became a victim of this continuing struggle, d...

This is happening everywhere, all year around, just because of the nature of actual Human Knowledge. Invited speakers: a bunch of people who all know what they're talking about . On light and the nature of photographic process: Silver halide crystals only go off when exposed to light at certain frequencies, so the crystals have to be embedded in a glycerine matrix with layers of dye to make the film respond to visible light. Subscribe to  Smarter Every Day 2 . See  Joel Hamkins interviewed on About Logic .

It's a real eye opener, this one! I got a bit carried away in the comments  because they asked for questions: Yes, this is great! 18:27 I have a question I would ask him on fictionalism / formalism / realism / structuralism: Aren't these Universes [which] Set Theory holds to be real objective things ultimately all models described in some metalanguage of their own? I'm just thinking of the tiny class of ones I have heard about, such as the Von Neumann cumulative hierarchy with this and that extra cardinals, say. It seems to take quite a lot to define V_\alpha let alone these higher cardinals, and isn't that new metalanguage just another language that one day will have to be formalised, and won't that require a new metalanguage and so on and so forth? So is it really those constructions which are real, or is there another more fundamental concept that is real, one that these are all just instances of? This seems to me to be the idea Lawvere had with the theory of the...

57:54  Lean ⊆ HoTT0. See  Vladimir Voevodsky - What if Current Foundations of Mathematics are Inconsistent .  Subscribe to  Formalization Seminar Cambridge . Subscribe to ItaLean Conference .  Thierry Coquand on Dependent type theory and formalization of mathematics (non-technical) The quality of the sound recording is not great, but it's worth it:  Subscribe to Andrei Rodin .  The state of the art in lean, three years ago: Subscribe to  Lean Prover Community .  I came here because I heard this talk by Simon Willerton last week and he seems to be able to interpret some ideas like extanaturality from higher category theory into 2-category theory, but I am not sure about that: he doesn't say that's what he's done, it's just how it seems to me.  Subscribe to  Topos Institute .