GTD Systèmes Dynamiques

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FEJOZ Jacques (Université Paris Dauphine)

Le 17/11/2025
De 10:00 à 11:00
Titre : Introduction à la dynamique de N vortex

Résumé :

Salle : C131

Séminaire Analyse-Probabilités

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CERCLÉ Baptiste (EPFL Lausanne)

Le 18/11/2025
De 10:30 à 11:30
Titre : Around the semi-classical limit of boundary Liouville theory

Résumé : Liouville theory provides a notion of random surface that "fluctuates" around a deterministic (=classical) one. This classical geometry corresponds to the unique solution of the problem of finding, within a given conformal class, a Riemannian metric with prescribed scalar and geodesic curvatures as well as conical singularities and corners. The level of randomness in Liouville theory is measured by the coupling constant $\gamma\in(0,2)$, the semi-classical limit corresponding to taking $\gamma\to0$. In this talk we will first discuss this classical geometry and the analytic tools used to study it. In a second part we will explain, thanks to its probabilistic formulation based on Gaussian Free Fields and Gaussian Multiplicative Chaos, that the semi-classical limit of boundary Liouville CFT indeed describes this classical geometry. If time permits we will discuss some implications of this semi-classical limit in relation with uniformisation of open Riemann surfaces.

Salle : A711

Rencontres statistiques

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REISACH Alexander (Université Paris Cité)

Le 24/11/2025
De 13:45 à 14:45
Titre : The Case for Time in Causal DAGs

Résumé : Graphical causal models, usually in the form of directed acyclic graphs (DAGs), are a central model class for encoding and reasoning about causal relationships between different quantities. In contrast to other causal models, they do not encode the temporal relationship between variables explicitly. We demonstrate that such nontemporal causal DAGs are ambiguous and obstruct justification of the acyclicity assumption. Assuming that causes precede effects, causal relationships are relative to the time order, and causal DAGs require temporal qualification. We propose a formalization via "composite" causal variables that refer to quantities at one or multiple time points. We emphasize that the acyclicity assumption requires different justifications depending on whether the time order allows cycles. We conclude by discussing implications for the interpretation and applicability of DAGs as causal models.

Salle : P205

Groupe de travail ESCAPADE

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SECK Abdou (Dauphine)
ABDOU SECK
Le 24/11/2025
De 13:03 à 14:03
Titre : Test6
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Résumé : eznkjifjed fhdb cedhsfcdhsjcher dscsd

Salle : C621 - Lien teams : Rejoindre le séminaire

Séminaire Analyse-Probabilités

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DAVID Noemi (CNRS and LMRS - Université de Rouen)

Le 25/11/2025
De 10:30 à 11:30
Titre : Singular limits in mechanical models of tissue growth

Résumé : Based on the mechanical viewpoint that living tissues exhibit a fluid-like behavior, PDE models inspired by fluid dynamics are now well established as one of the main mathematical tools for the macroscopic description of tissue growth. Depending on the type of tissue, these models link the pressure to the velocity field using either Brinkman’s law (viscoelastic models) or Darcy’s law (porous medium equations, PME). Furthermore, the stiffness of the pressure law plays a crucial role in distinguishing density-based (compressible) models from free-boundary (incompressible) problems, in which the density is saturated. In this talk, I will show how to connect different mechanical models of living tissues through singular limits. In particular, I will discuss the inviscid limit toward the PME, the incompressible limit of the PME leading to free-boundary problems of the Hele-Shaw type, and finally the joint limit.

Salle : A711

GTD Systèmes Dynamiques

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LEGUIL Martin (CMLS École Polytechnique)

Le 01/12/2025
De 10:15 à 11:15
Titre : Rigidité en dynamique hyperbolique & applications en géométrie

Résumé :

Salle : P203

Colloquium du CEREMADE

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BACH Francis (INRIA, ENS & PSL)

Le 02/12/2025
De 15:30 à 16:30
Titre : Denoising diffusion models without diffusions

Résumé : Denoising diffusion models have enabled remarkable advances in generative modeling across various domains. These methods rely on a two-step process: first, sampling a noisy version of the data—an easier computational task—and then denoising it, either in a single step or through a sequential procedure. Both stages hinge on the same key component: the score function, which is closely tied to the optimal denoiser mapping noisy inputs back to clean data. In this talk, I will introduce an alternative perspective on denoising-based sampling that bypasses the need for continuous-time diffusion processes. This framework not only offers a fresh conceptual angle but also naturally extends to discrete settings, such as binary data. Joint work with Saeed Saremi and Ji-Won Park.

Salle : A709

Séminaire Analyse-Probabilités

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VANNEUVILLE Hugo (Institut Fourier (Université Grenoble Alpes))

Le 09/12/2025
De 10:30 à 11:30
Titre : TBA

Résumé : TBA

Salle : A711

GTD Systèmes Dynamiques

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LEGUIL Martin (CMLS École Polytechnique)

Le 15/12/2025
De 10:15 à 11:15
Titre : Rigidité en dynamique hyperbolique & applications en géométrie

Résumé :

Salle : D204

Séminaire Analyse-Probabilités

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SALORT Delphine (LJLL)

Le 16/12/2025
De 10:30 à 11:30
Titre : TBA

Résumé : TBA

Salle : A711