séminaires et groupes de travail




ID de réunion : 865 2139 7722
Code secret : 944115

17 octobre 2022 Salle 4336, Pavillon A. Aisenstadt, CRM

9h15 Claire GUERRIER (Université de Nice et IRL) Détecter l’activité synaptique dans les données de ‘calcium imaging’

10h00 Thomas HAETTEL (IUT Montpellier et IRL) Espaces métriques injectifs

10h45 Mylene MAIDA (Université de Lille et IRL) Mots en des permutations aléatoires

11h30 Youness LAMZOURI (Université de Lorraine et IRL) La répartition des sommes du symbole de Legendre


13h15 Olivier LAFITTE (Sorbonne Paris Nord et IRL) Solutions analytiques pour le couplage de modèles: neutronique-thermohydraulique.

14h00 Chi TRAN (Université Gustave Eiffel et IRL) Arbre radial couvrant dans l’espace hyperbolique



Clair Poignard, INRIA Bordeaux Sud Ouest, Wednesday November 24th, 2021 Electroporation at the cell scale
Room 5340, Universite de Montreal, Pavillon Aisenstadt
Electropermeabilization (also called electroporation) is a significant
increase in the electrical conductivity and permeability of the cell
membrane that occurs when pulses of large amplitude (a few hundred
volts per centimeter) are applied to the cells: due to the electric
field, the cell membrane is permeabilized, and then nonpermeant
molecules can easily enter the cell cytoplasm by diffusion through the
electropermeabilized membranes. If the pulse duration is sufficiently
short (a few milliseconds or a few microseconds, depending on the
pulse amplitude), the cell membrane reseals within several tens of
minutes: reversible electroporation,  preserves the cell viability and
is used in electrochemotherapy to vectorize the drugs until the cell
inside.   If the pulses are too long, too numerous or if their
amplitude is too high, the cell membrane is irreversibly destroyed and
the cells are killed. Irreversible electroporation provides thus a
novel non thermal an minimally invasive ablation therapy.

In this talk I will present the state of the art on the mathematical
models of cell electroporation, and on going work on the modeling of
the micro-tissue response to electrical shocks. I will also illustrate
how numerical models can help interventional radiologists in their
practice of percutaneous tumor ablation by irreversible

Vendredi 3 juin 2022

Salle PK-4323 au LACIM (laboratoire du CRM), Université du Québec à Montréal

13h30 Albert COHEN Laboratoire Jacques-Louis Lions, Sorbonne Université

Titre: Optimal sampling in least-squares methods

Recovering an unknown function from finitely many point samples is an ubiquitous task in various  applicative settings: non-parametric regression, machine learning, reduced modeling, response surfaces in computer or physical experiments, data assimilation and inverse problems. In this lecture, I will present recent results that are relevant to the context where the user is allowed to select the measurement points, sometimes refered to as active learning. These results allow us to derive an optimal sampling point distribution when the approximation is searched in a linear space of finite dimension n and computed by weigted-least squares.
Here optimal means both that the approximation is comparable to the best possible in this space, and that the sampling budget m barely exceeds n. The main involved  tools are Christoffel functions, matrix concentration inequalities, reproducing kernel Hilbert spaces.


14h25 Viviane PONS, IRL CRM et Laboratoire Informatique pour la Mécanique et les Sciences de l’Ingénieur, Université Paris Saclay

Titre : treillis du s-ordre faible et s-Tamari

Nous présentons deux objets combinatoires classiques : le treillis de l’ordre faible sur les permutations et le treillis de Tamari. Dans les deux cas, le diagramme de Hasse modélisant la relation d’ordre partiel est le squelette d’un polytope : respectivement le permotoèdre et l’associaèdre. On montrera comment on peut généraliser cette construction pour obtenir deux nouveaux treillis et les constructions géométriques associées.

15h00 Claire GUERRIER, IRL CRM et Laboratoire Dieudonné, Université de Nice et de la Côte d’Azur

Titre: Signal propagation in myelinated axons: relating structure to function using mathematical modeling and simulations.

How myelin sheath characteristics influence spike transmission within myelinated axons and vice-versa?To address this question, we develop a model for signal transmission in the myelinated axon where myelin compartments alternates with nodes of Ranvier. The model is based on cable theory and Hodkin-Huxley formalism,  and the analysis relies on the heat equation. Using a computational approach coupled to mathematical analysis, we determine the analytical solution corresponding to signal propagation in one myelin compartment, and investigate the signal transmission time for different neuronal morphology.

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séminaires donnés par les chercheurs de l’IRL au CRM

31 octobre 2022

McGill, Burnside Hall, 1104

Zeldovich-Von Neumann Doring detonation theory

Olivier Lafitte, UMI-CRM


31 octobre 2022 – 16:00:00

Séminaire Physique Mathématique
Pour obtenir les accès Zoom veuillez vous inscrire aux listes de votre choix / To get your Zoom access, please subscribe to the lists of your choice: https://forms.gle/axqFGSkRkbkdFtE68

Uses of centralizer algebras and the missing label of SU(3)

Loïc Poulain d’Andecy, Université de Reims Champagne Ardenne


29 septembre 2022 – 14:30:00 – 16:00:00

Séminaire Québec-Vermont Number Theory
Concordia University, Library Building, 9th floor, room LB 921-4

The distribution of quadratic character sums

Youness Lamzouri, Université de Lorraine, CNRS-CRM


8 septembre 2022 – 11:30:00 – 12:30:00

Séminaire Probabilités / Probability
There will be no Zoom link for this week Sur place / in person – McGill, Burnside Hall, room 1214

A statistical physics approach to the Sine beta process

Mylène Maïda, Lille


19 novembre 2021 – 11:00:00 – 12:00:00

Séminaire LACIM
201, Ave. du Président-Kennedy, Local PK-4323, Montréal P.Qué.

Le tri permutarbre

Viviane Pons, LISN, Université Paris-Saclay


19 mars 2021 – 15:00:00 – 16:00:00

Colloque Colloque des sciences mathématiques du Québec
Zoom: pour inscription/ To register: http://crm.umontreal.ca/colloque-sciences-mathematiques-quebec/#csmq

ABCD asymptotic expansion for lattice Boltzmann schemes and application to compressible Navier Stokes equations

François Dubois, Le CNAM – Paris Member of IRL-CRM CNRS / Membre IRL-CRM CNRS