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.
On optimal transport under the causality constraint.
Abstract: In this talk we shall examine causal transports and the associated optimal transportation problem under the causality constraint (Pc). Loosely speaking, causal transports are a relaxation of adapted processes in the same sense as Kantorovich transport plans are the extension of Monge-type transport maps. We will establish a simple primal-dual picture of both (Pc) and the so-called bicausal transportation problem (whereby causality runs in both directions) in euclidean space or equiv. for discrete-time processes. Together with...
Macroscopic energy fluctuations: from normal diffusion to superdiffusion in the evanescent noise limit
RESUMEN: Over the last few years, anomalous behaviors have been observed for one-dimensional chains of oscillators. Recently, Bernardin, Gonçalves and Jara proved the following result: when the one-dimensional system is given by an unpinned harmonic chain of oscillators perturbed by an energy-momentum conserving noise, the energy fluctuation field at equilibrium evolves according to an infinite dimensional 3/4-fractional Ornstein-Uhlenbeck process. This talk will aim to understand the regime transition for the energy fluctuations....
Loving and Loathing: Portrayals of mathematics in Young Adult fiction novels
Abstract In the western world many students choose not to study more advanced mathematics because they develop negative identities as learners of mathematics. Students develop these attitudes, not just from school, but also from the views of mathematics held and perpetrated in society. How does society view mathematicians and the subject of mathematics? Research into the images in popular culture reveal portrayals of mathematics as hard, logical, certain and ultra-rational and mathematicians as eccentric, highly emotional and even insane...
The Brezis-Nirenberg Problem on S^n, in spaces of fractional dimension.
Abstract: We consider the nonlinear eigenvalue problem, -\Delta_{\mathbb{S^n}} u = \lambda u + |u|^{4/(n-2)} u, with $u \in H_0^1(\Omega)$, where $\Omega$ is a geodesic ball in S^n. In dimension 3, this problem was considered by Bandle and Benguria. For positive radial solutions of this problem one is led to an ordinary differential equation (ODE) that still makes sense when n is a real rather than a natural number. Here we consider precisely that situation with 2<n<4. Our main result is that in this case one has a...
Extragradient method with variance reduction for pseudo-monotone stochastic variational inequalities
Resumen: We propose an extragradient method with stepsizes bounded away from zero for stochastic variational inequalities requiring only pseudo-monotonicity. We provide convergence and complexity analysis, allowing for an unbounded feasible set, unbounded operator, non-uniform variance of the oracle and, also, we do not require any regularization. Alongside the stochastic approximation procedure, we iteratively reduce the variance of the stochastic error. Our method attains the optimal oracle complexity O(1/epsilon^2) (up to a logarithmic...
Herramientas para formación de profesores de educación básica basadas en experiencias de enseñanza de la matemática en aula
RESUMEN En esta charla reportaremos los avances del proyecto FONDEF IT 10003 Herramientas para fortalecer la formación de profesores de educación básica basadas en experiencias de enseñanza de la matemática en aula. El objetivo de este proyecto es desarrollar un modelo de formación que permita acercar el aula escolar a la formación universitaria de los profesores, lo que incluye la elaboración de un texto de actividades de aula y material audiovisual para formación inicial, y el desarrollo de una capacitación para académicos formadores de...
Robin Grimes’ seminar: The Inexhaustible Rise of Computer Simulation
The researcher at Imperial College of London, and Chief Scientific Adviser at the Foreign and Commonwealth Office, discusses the rise in simulation and what the future may hold for scientific computing.
Asymptotic Stability of solitons of the high dimensional Zakharov-Kuznetsov equation
Abstract: In this talk I will discuss a recent work with R. Cote, D. Pilod and G. Simpson, where we consider solitons of the high dimensional Zakharov-Kuznetsov equation, a model of plasma ions in Physics. In particular, we prove that solitons are strongly asymptotically stable in the energy space, in a particular region of the plane determined by natural geometrical and dispersive constraints. To prove this result we extend to the high dimensional case several tools coming from the one-dimensional setting (generalized KdV equations),...
Graphs with the same chromatic symmetric function
ABSTRACT: In 1995 Stanley introduced the chromatic symmetric function associated to every simple graph. In this talk, I’ll present a novel technique to write this function as a linear combination of symmetric chromatic functions for smaller graphs. I will give two applications of this technique, the first is a sufficient condition for two graphs to have the same chromatic symmetric function; and the second is a construction of pairs of unicyclic graphs with the same symmetric chromatic function. In addition, I will discuss some...
Convex Nonlinear Relaxations of the Pooling Problem
Resumen: We investigate relaxations for the non-convex pooling problem, which arises in production planning problems in which products with are mixed in intermediate “pools” in order to meet quality targets at their destinations. We derive valid nonlinear convex inequalities, which we conjecture define the convex hull of this continuous non-convex set for some special cases. Numerical illustrations of the results will be presented.
