The Eternal Doorman

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 . 

See  https://niunamenos.ar/ .  Subscribe to Pupina Plomer .

At around 34:00 you get a glimpse of why measure theory is such a mess!  See Charles Fefferman's 1971 paper  The multiplier problem for the ball . Jonathan Hickman's 2025 paper:  The Kakeya Conjecture: where does it come from and why is it important?   Subscribe to John Baez .

With a guest host in North Carolina,... See  Spiritually Depraved, Misery Inducing Landscapes of North America Episode III .  Compare this with Brad Lancaster's barrio in Tucson: See Urban Planning Problems and Americans Doing Real Science . Subscribe to Crime Pays but Botany Doesn't . 

See  An Open Letter to Chancellor Friedrich Merz . So-called leaders behaving like children.  Richard Wolff a few days ago:  Subscribe to Glenn Diesen .