Journées ANR Conviviality
de
mercredi 20 mai 2026 (14:00)
à
vendredi 22 mai 2026 (14:00)
lundi 18 mai 2026
mardi 19 mai 2026
mercredi 20 mai 2026
14:00
TBA
-
Michel Bonnefont
TBA
Michel Bonnefont
14:00 - 15:00
15:00
On set-valued intertwining duality for diffusion processes
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Laurent Miclo
On set-valued intertwining duality for diffusion processes
Laurent Miclo
15:00 - 16:00
Markov intertwinning relations were first developed in the finite state space setting to provide a probabilistic approach to convergence to equilibrium. We will see how to adapt this method to diffusions on Riemannian manifolds, through stochastic extensions of mean curvature flows.
16:00
Pause
Pause
16:00 - 16:30
16:30
TBA
-
Marjolaine Puel
TBA
Marjolaine Puel
16:30 - 17:30
17:30
On weighted Poincaré inequalities for multivariate Liouville and elliptical distributions - Application to Global Sensitivity Analysis
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David Heredia
On weighted Poincaré inequalities for multivariate Liouville and elliptical distributions - Application to Global Sensitivity Analysis
David Heredia
17:30 - 18:00
In this work, we develop new weighted Poincaré inequalities for two clases of multivariate probability measures: multivariate Liouville and elliptical contoured distributions. The former are established via a radial-type decomposition involving the Dirichlet distribution, while the latter are obtained through their spherical counterparts. We further extend this type of results to measures with prescribed copulas. Finally, we apply these results to global sensitivity analysis and illustrate their practical use in a flood model case study.
18:00
TBA
-
Ons Rameh
TBA
Ons Rameh
18:00 - 18:30
jeudi 21 mai 2026
09:00
Sub-exponential tails in biased run and tumble equations with unbounded velocities
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Luca Ziviani
Sub-exponential tails in biased run and tumble equations with unbounded velocities
Luca Ziviani
09:00 - 09:30
Run and tumble equations are widely used models for bacterial chemotaxis. In this talk, we present the long-time behavior of run and tumble equations with unbounded velocities. We show existence, uniqueness and quantitative convergence towards a steady state. In contrast to the bounded velocity case, the equilibrium has sub-exponential tails and we have sub-exponential rate of convergence to equilibrium. This produces additional technical challenges. We are able to successfully adapt both Harris' type and L²-hypocoercivity. This is joint work with Emeric Bouin and Josephine Evans.
09:30
TBA
-
Jordan Serres
TBA
Jordan Serres
09:30 - 10:30
10:30
Pause
Pause
10:30 - 11:00
11:00
Régularité des équations elliptiques à poids monomiaux
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Francesco Pagliarin
Régularité des équations elliptiques à poids monomiaux
Francesco Pagliarin
11:00 - 11:30
Dans cet exposé je présenterai des théorèmes de régularité $C^{0,\alpha}$ et $C^{1,\alpha}$ pour solutions d'équations elliptiques, en forme de divergence, avec poids monomiaux. A cause de la dégéneration/singularité des poids (qui ne sont pas forcement dans la classe des poids Muckenhoupt $A_2$) la théorie classique ne s'applique pas. Grace à des théorèmes d'approximations et à des inegalités de Sobolev uniformes en $\epsilon$ on pourra quand même démontrer la régularité holderienne des solutions. C'est un travail fait en collaboration avec G. Cora, G. Fioravanti et S. Vita.
11:30
TBA
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Tom Maitre
TBA
Tom Maitre
11:30 - 12:00
12:00
Repas
Repas
12:00 - 14:00
14:00
Les variables sous-gaussiennes sont somme de trois gaussiennes, d'après A. Song
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Max Fathi
Les variables sous-gaussiennes sont somme de trois gaussiennes, d'après A. Song
Max Fathi
14:00 - 15:00
Dans cet exposé, je présenterai des résultats récents de Antoine Song sur une conjecture prédisant que les variables 1 sous-gaussiennes peuvent être réalisées comme sommes d'un nombre borné de variables gaussiennes standard, en toutes dimensions. Song démontre cette conjecture en dimension 1, et donne des nouvelles estimations sur le nombre de gaussiennes nécessaires en dimension supérieure. Je parlerai aussi des motivations de ce problème, issues de la géométrie des convexes.
15:00
TBA
-
Andreas Malliaris
TBA
Andreas Malliaris
15:00 - 15:30
15:30
Pause
Pause
15:30 - 16:00
16:00
TBA
-
Pierre Gervais
TBA
Pierre Gervais
16:00 - 17:00
17:00
Low-temperature asymptotics of the Poincaré and the log-Sobolev constants for Łojasiewicz potentials
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Aziz Ben Nejma
Low-temperature asymptotics of the Poincaré and the log-Sobolev constants for Łojasiewicz potentials
Aziz Ben Nejma
17:00 - 17:30
In 2024, Chewi and Stromme showed that, in the low-temperature regime, the behavior of the relative entropy with respect to a Gibbs measure reflects that of the underlying potential when the latter has a unique minimizer. They conjectured that this link extends more generally to potentials having multiple minimizers. In this talk, we show that this is not the case. We explain that when there are multiple minimizers, the geometry of the set of minimizers plays a direct role in how the constants in functional inequalities behave at low temperature.
17:30
TBA
-
Ivan Gentil
TBA
Ivan Gentil
17:30 - 18:15
vendredi 22 mai 2026
09:00
TBA
-
Patrick Cattiaux
TBA
Patrick Cattiaux
09:00 - 10:00
10:00
TBA
-
Louis-Pierre Chaintron
TBA
Louis-Pierre Chaintron
10:00 - 10:45
10:45
Pause
Pause
10:45 - 11:15
11:15
TBA
-
Paul Invernizzi
TBA
Paul Invernizzi
11:15 - 11:45
11:45
Active Brownian particles with mean-field interaction: singular interactions and multiple invariant measures
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Oscar de Wit
Active Brownian particles with mean-field interaction: singular interactions and multiple invariant measures
Oscar de Wit
11:45 - 12:30
We introduce a mean-field McKean-Vlasov model for a collective of ants. The model sustains two non-trivial dynamical behaviours: aggregation and lane formation. We show the well-posedness and mean-field limit for the particle model with singular interactions via a compactness method. We also show the existence of multiple invariant measures via perturbative Fourier-style bifurcation analysis, reflecting the aggregation and lane formation behaviours (joint work with Matthias Rakotomalala). We conclude with some open problems pertaining to interacting active Brownian particle models.
12:30
Repas
Repas
12:30 - 14:00