Noticias en español
Seminars appear in decreasing order in relation to date. To find an activity of your interest just go down on the list. Normally seminars are given in English. If not, they will be marked as Spanish Only.
Facilitated Exclusion Process and Stefan Problem.
Resumen: We consider an exclusion-type particle process on Z, in which a particle can only jump if it is “pushed” by another particle. We show that the hydrodynamic limit is given by a Stefan problem, and that the active/inactive phases at the micro- and macroscopic levels coincide. Joint work with Clément Erignoux and Marielle Simon.
Sigma-convex functions and Sigma-subdifferentials.
Abstract: In this talk we present and study the notion of $\sigma$-subdifferential of a proper function $f$ which contains theClarke-Rockafellar subdifferential of $f$ under some mild assumptions on $f$. We show that some well known properties of the convex function, namely Lipschitz property in the interior of its domain, remain valid for thelarge class of $\sigma$-convex functions.
Un par de modelos epidemiológicos para la COVID-19.
Abstract: En esta charla voy a hablar sobre modelos epidemiológicos y las dificultades que un físico se puede encontrar cuando aborda nuevos campos. En concreto, veremos dos modelos diferentes en los que, además, se considera una variante que incluye dos grupos de edad diferentes. Estos modelos se aplican a diferentes regiones y/o países, como la comunidad autónoma de Andalucía en España, México, Grecia o Portugal. También hablaré sobre problemas como la identificabilidad de los parámetros y el cálculo de intervalos de...
Elementos de distorsión en el grupo de difeomorfismos de la esfera.
ABSTRACT: En esta charla estudiaremos algunas propiedades dinámicas, fuera del mundo de la medida, de los elementos de distorsión en el grupo de difeomorfismos de la esfera.
Observación de la Tierra para el monitoreo de sequía en Chile.
Participación en Linea: http://vcespresso.redclara.net/@352109705c115cdd511fb968f9f4ff86# Use Explorer, Firefox o Safari.
Ramsey Goodness of trees in random graphs.
Abstract: In 1977, Chvátal proved that every blue-red coloring of the edges of the complete graph on rn+1 vertices yields either a blue copy of the complete graph on r vertices or a red copy of each tree with r edges. This result was further extended by Burr and Erdős in 1983, starting a topic now known with the name of Ramsey goodness. In this talk, we will discuss a random analog of Chvátal’s theorem in sparse random graphs, which is one of the first results for Ramsey numbers of large graphs in sparse random graphs. If time permits,...
Online assortment optimization for two-sided matching platforms.
Abstract: Motivated by online labor markets, we consider the online assortment optimization problem faced by a two-sided matching platform that hosts a set of suppliers waiting to match with a customer. Arriving customers are shown an assortment of suppliers, and may choose to issue a match request to one of them. Before leaving the platform, each supplier reviews all the match requests he has received, and based on his preferences, he chooses whether to match with a customer or to leave unmatched. We study how platforms should design online...
Modelos topológicos de sistemas loosely Bernoulli con entropía cero.
ABSTRACT: Daremos una caracterización puramente topológica de sistemas dinámicos únicamente ergódicos cuya medida tiene entropía cero y es loosely Bernoulli. Para esto usaremos la pseudo métrica de Feldman-Katok. Algunos ejemplos que caen en esta categoría son horociclos, sistemas de rango finito y distales. Trabajo en conjunto con Dominik Kwietniak.
A new solution to $\Delta u+u^p-u=0$ on the entire space.
Abstract: In this talk we develop some techniques to construct solutions of certain semilinear elliptic equations which are periodic in some variables, decaying in others, and quasiperiodic in one variable. These solutions, which are found near ground states of a lower-dimensional problem, are constructed using spatial dynamics and results from the KAM theory. The use of a suitable KAM-type theorem provides hypotheses for homogeneous equations which rely on simple scaling arguments, applying in particular to $\Delta u+u^p-u=0$ with $p>1$...
Generalized Newton Algorithms for Tilt-Stable Minimizers in Nonsmooth Optimization.
Abstract: This talk aims at developing two versions of the generalized Newton method to compute local minimizers for nonsmooth problems of unconstrained and constraned optimization that satisfy an important stability property known as tilt stability. We start with unconstrained minimization of continuously differentiable cost functions having Lipschitzian gradients and suggest two second-order algorithms of the Newton type: one involving coderivatives of Lipschitzian gradient mappings, and the other based on graphical derivatives of the...
