#Communiqué 🗞️ La médaille d'or 2025 du CNRS est décernée à Stéphane Mallat, mondialement reconnu pour ses travaux autour des mathématiques appliquées au traitement du signal et à l’intelligence artificielle. 👏 👉 cnrs.fr/fr/presse/en... #TalentsCNRS 🏅

Sur le marché public de ma fac, il y a deux hotels de disponible paris intra-muros (1 mois et demi en avance). Et pas "deux" comme une manière de dire peu, DEUX = D-E-U-X = 2. Putain de marché public à la con. Putain de règles administratives à la con.

20 years later I still love this city!

I'm BEYOND THRILLED to tell you that our first original song is now available on all platforms! Plz share if you like it 🙏🏼🙏🏼😊 Cheers

Congratulations to Dr. Sophie Jaffard @sophiejaffard.bsky.social for a brillant PhD defense! We were very lucky with Patricia to have you as a PhD student, and I am sure that you will have a brillant career ahead.

1/2 Julia Brun (M1) «Modèles particulaires de type Cucker-Smale et limites de champ moyen» gagne le prix K. Johnson 🎉 avec un voyage à Paris et visite de la Maison Poincaré #parité #maths #Nice06 #fillesEtMaths @cnrs-insmi.bsky.social @univcotedazur.bsky.social @cnrscotedazur.bsky.social

A reviewer in my batch submitted a review shorter than a tweet. wtf

AWS chatbot is amazing. Q: I cant login neither I can reset my password because phone number verification is not working. A: If you cant reset your password, login into your account to reset your MFA.

Expedition 33 might be overhyped. Let me add my contribution: This is an incredibile masterpiece.

New paper on the generalization of Flow Matching www.arxiv.org/abs/2506.03719 🤯 Why does flow matching generalize? Did you know that the flow matching target you're trying to learn *can only generate training points*? w @quentinbertrand.bsky.social @annegnx.bsky.social @remiemonet.bsky.social 👇👇👇

I am sure that the number of faculty follows the same curve /s

Ma matinée

It seems other authors* have just reached similar conclusions (large minibatches help for OT-CFM), using entropic-reg OT in place of our bilevel-sliced OT * Michal Klein, Alireza Mousavi-Hosseini, Stephen Zhang, @marcocuturi.bsky.social arxiv.org/abs/2506.05526

I wrote in my notes few years ago a *suboptimal* (and maybe wrong 😅) lower bounds of GD for smooth strongly convex function. Nesterov's proof uses seq w/ values in ℝ^ℕ (so infinite dimensional), whereas I do a similar strategy as in the convex case, ie in ℝ^n 1/3 samuelvaiter.com/intro-to-low...

I play Expedition 33 in story mode, and found it not that easy (*). This evening, I launched the game and was impressed with myself because I was much better at parrying than usual. And then I saw the patch notes ... 🥲 (*) translation: I'm getting slaughtered.

One of my papers with @sophiejaffard.bsky.social just turned one 🎂. No reviews yet, but I’m sure the reviewers are carefully choosing every word (one per day).

Le prochain Data Science Colloquium à l'ENS, jeudi 12 juin, sera donné par David Louapre d'Ubisoft, "What modern AI and neuroscience can bring to non-playing characters in video games". David c'est bien sûr également le vulgarisateur scientifique de www.youtube.com/scienceetonn...

📣 New preprint 📣 **Differentiable Generalized Sliced Wasserstein Plans** w/ L. Chapel @rtavenar.bsky.social We propose a Generalized Sliced Wasserstein method that provides an approximated transport plan and which admits a differentiable approximation. arxiv.org/abs/2505.22049 1/5

They say "emacs bankruptcy". I say Marie Kondo x dotemacs = ❤️

Most (?) misunderstood theorems in pop culture 1. Godel's incompleteness theorem 2. Curry-Howard correspondence 3. Universal approximation of neural networks

I have cleaned a bit my lecture notes on Optimal Transport for Machine Learners arxiv.org/abs/2505.06589

Convolution theorem: Fourier transform of the convolution of two functions (under suitable assumptions) is the product of the Fourier transforms of these two functions. buff.ly/aOamDMF

Dual numbers correspond to the completion of the real line with an nilpotent element ε different from 0. It can be thought as a universal linearization of functions, or as the forward-mode of automatic differentiation. buff.ly/vahZ0Fk

Convergence of iterates does not imply convergence of the derivatives. Nevertheless, Gilbert (1994) proposed an interversion limit-derivative theorem under strong assumption on the spectrum of the derivatives. buff.ly/MhK7qiI

Leader-follower games, also known as Stackelberg games, are models in game theory where one player (the leader) makes a decision first, and the other player (the follower) responds, considering the leader’s action. This is one the first instance of bilevel optimization.

The Matrix Mortality Problem asks if a given set of square matrices can multiply to the zero matrix after a finite sequence of multiplications of elements. It is is undecidable for matrices of size 3x3 or larger. buff.ly/lLmvvlo

The SAT problem asks whether a logical formula, composed of variables and (AND, OR, NOT), can be satisfied by assigning True to the variables. SAT is NP-complete along with 3-SAT, with clauses of three literals, while 2-SAT, is in P! buff.ly/mMLGbw4

The Krein-Milman theorem states that any compact convex subset of a locally convex topological vector space is the closed convex hull of its extreme points. In particular, the set of extreme points of a nonempty compact convex set is nonempty. buff.ly/6aYS8ox

The Stone-Weierstrass theorem states that any continuous function on a compact Hausdorff space can be uniformly approximated by elements of a subalgebra, provided the subalgebra separates points and contains constants. buff.ly/MbZOAG0

The Nesterov Accelerated Gradient (NAG) algorithm refines gradient descent by using an extrapolation step before computing the gradient. It leads to faster convergence for smooth convex functions, achieving the optimal rate of O(1/k^2). www.mathnet.ru/links/ceedfb...

The pinhole camera model illustrates the concept of projective projection. Light rays from a 3D scene pass through an (infinitely) small aperture — the pinhole — and project onto a 2D surface, creating an inverted image on the focal plan. monoskop.org/images/f/ff/...

Łojasiewicz inequality provides a way to control how close points are to the zeros of a real analytic function based on the value of the function itself. Extension of this result to semialgebraic or o-minimal functions exist. matwbn.icm.edu.pl/ksiazki/sm/s...

The fast inverse square root trick from Quake III is an algorithm to quickly approximate 1/√x, crucial for 3D graphics (normalisation). It uses bit-level manipulation and Newton's method for refinement. web.archive.org/web/20170729...

A Monge map, i.e., a solution to optimal transport Monge problems, may not always exist, be unique, or be symmetric with respect to the source and target distributions. It was one of the motivation to introduce Kantorovich relaxation. math.univ-lyon1.fr/~santambrogi...

Attouch’ theorem relates the (epi-) convergence of convex lsc functions to the convergence of their subdifferential seen as graph on the product between the space and its dual. gallica.bnf.fr/ark:/12148/b...

Brenier's theorem states that the optimal transport map between two probability measures for quadratic cost is the gradient of a convex function. Moreover, it is uniquely defined up to a Lebesgue negligible set. www.ceremade.dauphine.fr/~carlier/Bre...

The Weierstrass function is a famous example of a continuous function that is nowhere differentiable. It defies intuition by being continuous everywhere but having no tangent at any point. Introduced by Karl Weierstrass in 1872.

The proximal operator generalizes projection in convex optimization. It converts minimisers to fixed points. It is at the core of nonsmooth splitting methods and was first introduced by Jean-Jacques Moreau in 1965. www.numdam.org/article/BSMF...

Announcing : The 2nd International Summer School on Mathematical Aspects of Data Science mathsdata2025.github.io EPFL, Sept 1–5, 2025 Speakers: Bach @bachfrancis.bsky.social Bandeira Mallat Montanari Peyré @gabrielpeyre.bsky.social For PhD students & early-career researchers Apply before May 15!

The Berry-Esseen theorem quantifies how fast the distribution of the sum of independent random variables converges to a normal distribution, as described by the Central Limit Theorem (CLT). It provides an upper bound depending on skewness and sample size. terrytao.wordpress.com/2010/01/05/2...

Opinion of the day: we don't desk reject enough in ML. Too much energy is wasted in 4x reviewing papers that will *obviously* be rejected. Second opinion otd: we don't teach enough students to be positive. We should not seek how to reject a paper, but how to accept it. And yes, #1 has a role in #2

Bilevel optimization problems with multiple inner solutions come typically in two flavors: optimistic and pessimistic. Optimistic assumes the inner problem selects the best solution for the outer objective, while pessimistic assumes the worst-case solution is chosen.

Klein geometry, part of the Erlangen Program introduced by F. Klein, studies geometry via transformation groups. A Klein geometry is defined as a space X=G/H, where G is a Lie group acting transitively on X. This unifies classical geometries under symmetry.https://arxiv.org/abs/0807.3161

The Thom gradient conjecture states that the trajectory of a gradient flow of a real-analytic function must converge such that the secant converge also. It was proved by Kurdyka, Mostowski, and Parusiński in 2000. www.jstor.org/stable/2661354

The Fenchel conjugate f*(y) is the maximum vertical gap between the line yx and the graph of f. This maximum occurs where the line is tangent to the curve, meaning f'(x) = y. It captures the largest gap at that tangent point.

With respect to any multimodal models included in Llama 4, the rights granted under Section 1(a) of the Llama 4 Community License Agreement are not being granted to you if you are an individual domiciled in, or a company with a principal place of business in, the European Union. Aaaaa openness ...

The law of large numbers tells that the empirical mean of an integrable random sample converges towards its mean in probability (weak LLN) and almost surely (strong LLN). en.wikipedia.org/wiki/Law_of_...

The Johnson–Lindenstrauss Lemma states that a set of high-dimensional points can be mapped into a much lower-dimensional space while approximately preserving pairwise distances. This is useful for dimensionality reduction, clustering, etc. stanford.edu/class/cs114/...

Stein's Lemma states that for a normally distributed variable X, the expected value E[Xg(X)] = E[g’(X)] for any g absolutely continuous (derivative a.e.) such that E[|g’(X)|] < ∞. It is a central result for characterizing (close-to) Gaussian data arxiv.org/abs/2104.08302

Erdős–Rényi-Gilbert graph models are two random models introduced in 1959 sharing a lot of common properties. In particular, G(n, p) exhibits a sharp threshold for the connectedness for p ≈ n/ln n. www.renyi.hu/~p_erdos/195...