So, since three days ago, there's a new constant in mathematics, which one might call the “plane unit distance exponent”: the sup of all δ≥1 such that there exist unit distance graphs in the plane with n vertices and n^(1+δ) edges for arbitrarily large n.

Since my blog is in French, I normally write the blog post announcements in French as well, but this one might be worth repeating in English: I tried to explain the current state of AI in math, and what might happen in the future: www.madore.org/~david/weblo...

I'm amazed by the glamorification of French protests in the United States. Wait until they hear about grenades, LBDs, and how utterly ineffective protesting has been in the last decades.

Quoi, c'est David qui a pris cette photo emblématique de la guerre la plus épique de l'histoire de la Wikipédia en français, la guerre «“endive” contre “chicon”»? La gloiiiiire! J'ai l'impression de connaître le photographe du «lever de drapeau sur Iwo Jima»!

Un long rant sur mon blog (avec plein de digressions et 29 notes en bas de paragraphe) concernant la situation actuelle des IA vis-à-vis des maths. www.madore.org/~david/weblo...

The sphinx stirred. "Halt! If you seek to pass, you must solve my riddle, or I will kill you!" The wanderer skulking in the sphinx' shadow froze in place. "Riddless? It wishess to play a game of riddless? We know riddless, we do, my preciouss, we do!"

The Budapest type theory group is hiring a postdoc to work on higher observational type theory. lists.seas.upenn.edu/pipermail/ty...

Arthur Conan Doyle #BOTD in fancy dress as a Viking

À partir de son expérience d’enseignant-chercheur, Gaëtan Flocco analyse la montée des logiques managériales, de la compétition et de la précarité dans l’Université en France, montrant comment les universitaires eux-mêmes contribuent à ces transformations 👇 www.contretemps.eu/illusions-et...

Paris.

Mouettes et goélands : on a l'impression qu'ils pullulent parce qu'on les trouve de plus en plus loin des mers, mais en réalité, ils sont en *déclin*. Des chiffres au UK :

Euh. NON @laquadrature.bsky.social, le contrôle de l'âge pour les sites #pornographiques n'est PAS une RÉUSSITE. Outre le caractère fantaisiste de laisser une IA évaluer l'âge, rien ne garantit que l'IA ne conservera pas un jour les visages afin de constituer un fichier. ❌ #ReconnaissanceFaciale

Présenter sa carte d'identité ou utiliser FranceConnect sera-t-il bientôt obligatoire pour accéder aux réseaux sociaux ? C'est ce que prépare une proposition de loi imposant une vérification d'âge pour empêcher les moins de 15 ans d'utiliser ces plateformes. www.laquadrature.net/2026/05/21/d...

Wait, Will Sawin has already improved on the result published ONLY YESTERDAY by OpenAI? 🤯 arxiv.org/abs/2605.20579

Born on this day in 1471, the incomparable Albrecht Durer. Just a complete dandy in his 1498 self portrait. I mean, the cap! The braided strap! And the gloves!! Not to mention the long curly locks.

Si je devais résumer aux huiles du ministère le décrochage de la recherche française je dirais: je doute que mon collaborateur américain réceptionne, signe (en bleu) et scanne les bons de livraison des consommables...

OK, here's one notable thing we can say eyeballing this unlabeled graph which I ❁think❁ represents probability of success at solving the problem as a function of log of thinking time: it appears to be roughly quadratic (p ∝ log(T)²). Does the 2 mean anything?

Do we have information on how many problems OpenAI tacked UNsuccessfully? Or how many runs of the LLM they needed to go through before finding a successful answer? How much thinking time (or token count) was involved? What the approximate cost / energy consumption was? Or is all this a secret?

La Westphalie, berceau du #ClubContexte. @gro-tsen.bsky.social

🔽 Announcement is at openai.com/index/model-... — with links to the annotated proof and comments by various experts. Interestingly, these (OpenAI-chosen) experts seem to mostly agree the main reason humans were stuck on the problem is they were trying to prove it rather find a counterexample.

Razorbills have the slickest design in the animal kingdom. They look like they were made by Yves Saint Laurent

‣ Atheism is the belief that God does not exist. ‣ Polytheism is the belief that God exists but is not unique. ‣ Christianity is the belief that God exists and is unique, but not up to a unique isomorphism, because He has a non-trivial automorphism of order 3.

Je fais un nombre faramineux de likes sur le Bad Place grâce à des informations que je dois à @pverschu.eurosky.social ici. x.com/gro_tsen/sta...

When I search for driving directions using Google Maps on my phone, then connect my phone to my car using Android Auto, the directions aren't shown by default — in fact, they're not even shown in the history. Is this bad UI or do I not know how to use it?

Good morning! 🪶

1893, ton médecin te dit qu'il a l'impression d'avoir déjà lu quelque chose qui lui fait penser à ton cas, il fouille dans sa bibliothèque et il te sort ça :

Ouais, comme la mafia répond à des besoins auxquels la police ne peut pas toujours répondre seule, ou parfois fait preuve d'une agilité et d'une rapidité qui sont parfois spectaculaires

L'université serait plus agile et rapide si la moindre action n'était pas compliquée administrativement jusqu'à l'absurde ; peut-être que le Ministère pourrait se saisir du sujet ?

Craziest thing about lean.py? You can roll your own (almost) feature-parity successor to Dafny. Python programs. Lean obligations. Grind as a solver. Proof complete. Program verified. Python code. Real.

A rich, thorough exploration of infinity that combines mathematical precision with playful, accessible coverage of a fascinating variety of paradoxes and conundrums. Joel David Hamkins' "The Book of Infinity" publishes in August! mitpress.mit.edu/978026205401...

The trick is, when among mathematicians, to say you are a physicist so that they forgive you for not knowing very much math. Then, when among physicists, say you are a mathematician so that they forgive you for not knowing very much physics. In especially dire cases I might say I am a philosopher.

Ils ont cassé mon degrémètre.

I wrote a long answer on MathOverflow showing that the “Scott formula” ((¬¬p⇒p) ⇒ (p∨¬p)) ⇒ (¬¬p∨¬p) is not realizable in Kleene's first algebra 𝒦₁ but ✺does✺ have a computable realizer in Kleene's 𝒦₂: mathoverflow.net/a/511442/17064 (my answer is somewhat self-contained: I recalled what this means)

Very interesting. Springer retracted two essays from the early 1940s by Max Planck. Apparently because of "duplicate publication" - similar things (also by Planck) appeared elsewhere. But back in the day, that was common and not thought of as bad! There wasn't an internet to spread papers around.

Biggest weakness

#ClubContexte: Ne pas confondre: ‣ le tunnel du Gothard fr.wikipedia.org/wiki/Tunnel_... (ouvert en 1882) ‣ le tunnel routier du Gothard fr.wikipedia.org/wiki/Tunnel_... (ouvert en 1980) ‣ le tunnel de base du Gothard fr.wikipedia.org/wiki/Tunnel_... (ouvert en 2016) ‣ le second tunnel routier …

I feel like maybe some people are skipping over the bit where Helen of Troy was HATCHED FROM AN EGG. I'll just leave this depiction from Metaponto here in case anyone needs it. (Photo by @diffendale.bsky.social)

"L’expression tire son nom de Thucydide, auteur de History of the Peloponnesian War" Huhuhu

Waheyy

Ah oui bien sûr, la frange antisémite du mouvement anti-crème solaire(?!) Comment ai-je pu ne pas y penser

“So what do you do?” “I'm a mathematician.” “Oh cool! Can you teach me a few tricks? Is it all done with smoke and mirrors?”

Two new facts stand out: 1. 85% of hallucinated citations in preprints are also in the subsequent journal version (thanks, peer review!) 2. Fake cites more likely to use the names of (male) scholars who are already highly cited, creating a fake-citation Matthew effect. arxiv.org/abs/2605.07723

Wow: you can knock out a plant with anesthetics - the same anesthetics that work on people! It's obvious for plants that move, like a Venus fly trap, but experiments have shown it's true for others too. We're still struggling to figure out what this means. pmc.ncbi.nlm.nih.gov/articles/PMC...

Par curiosité, je viens de regarder le temps en transports en commun entre l'Université de Versailles Saint-Quentin¹ et l'Université de Versailles Saint-Quentin². 😱 1. UFR des Sciences (ave. des États-Unis à Versailles) 2. Bâtiment d'Alembert (bd. d'Alembert à Guyancourt)

Mon (seul) ancien doctorant a eu un poste de MdC. 🍾

Votre rappel quotidien qu'en l'état actuel des choses, quasiment la seule question qui ait un sens sur l'Éducation nationale est "Comment faire pour recruter assez de profs pour assurer les cours ?" et la seule réponse est "Améliorer significativement la rémunération et les conditions de travail".

“Calm down, Edna. … Yes, it’s some giant, hideous insect … but it could be some giant, hideous insect in need of help.”