Seminars

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.

 

Perturbations of interpolations formulas.

Event Date: Nov 25, 2021 in Differential Equations, Seminars

Abstract: In this talk we will discuss some problems related to the theory of Fourier interpolation. The goal is to talk about the general problem of how to obtain new interpolation formulas from a previously known one by some perturbation argument, and also mentions some recent developments in joint work with João Pedro Ramos (ETH Zürich). This talk is meant for a broad audience with basic knowledge in analysis.

Transiciones de fase y cuasi-cristales.

Event Date: Nov 22, 2021 in Dynamical Systems, Seminars

ABSTRAC:  En esta charla revisaré resultados recientes sobre transiciones de fase de potenciales asociados a algunos subshitfs sustitutivos (cuasi-cristales).  En particular, revisaremos los resultados de Bruin y Leplaideur para el subshift de Fibonacci, y discutiremos posibles generalizaciones.

Diversos resultados en covers monocromáticos.

Event Date: Nov 22, 2021 in Seminario de Grafos, Seminars

Abstract: En este seminario veremos algunos resultados bajo distintas condiciones sobre covers monocromáticos extraídos del artículo ( https://arxiv.org/pdf/2009.07239.pdf ). Entre las condiciones a presentar se encuentran restricciones en los colores, subgrafos de diámetro acotado, entre otros.

Variants of the A-HPE and large-step A-HPE algorithms for strongly convex problems with applications to accelerated high-order tensor methods.

Event Date: Nov 17, 2021 in Optimization and Equilibrium, Seminars

 Abstract: For solving strongly convex optimization problems, we propose and study the global convergence of variants of the A-HPE and large-step A-HPE algorithms of Monteiro and Svaiter. We prove linear and the superlinear $\mathcal{O}\left(k^{\,-k\left(\frac{p-1}{p+1}\right)}\right)$ global rates for the proposed variants of the A-HPE and large-step A-HPE methods, respectively. The parameter $p\geq 2$ appears in the (high-order) large-step condition of the new large-step A-HPE algorithm. We apply our  results to high-order tensor methods,...

Error Bounds for the One-Dimensional Constrained Langevin Approximation for Density Dependent Markov Chains.

Event Date: Nov 17, 2021 in Seminario de Probabilidades de Chile, Seminars

Resumen:  The stochastic dynamics of chemical reaction networks are often modeled using continuous-time Markov chains. However, except in very special cases, these processes cannot be analysed exactly and their simulation can be computationally intensive. An approach to this problem is to consider a diffusion approximation. The Constrained Langevin Approximation (CLA) is a reflected diffusion approximation for stochastic chemical reaction networks proposed by Leite & Williams. In this work, we extend this approximation to (nearly) density...

Conjuntos de Meyer, sistemas dinámicos y valores propios.

Event Date: Nov 15, 2021 in Dynamical Systems, Seminars

ABSTRACT: En esta charla vamos a comenzar definiendo conjuntos de Meyer y algunos ejemplos. También, partiendo desde un conjunto de Meyer, definiremos un sistema dinámico. Luego, usando la address map introducida por J. Lagarias en 1999, mostraremos un resultado que nos permite encontrar valores propios para este sistema dinámico. Como aplicación de este resultado, caracterizamos una subclase de conjuntos de Meyer llamados model sets Euclidianos. Este es un trabajo en conjunto con Daniel Coronel.

Ciclos Hamiltonianos factores triangulares en grafos pseudo-aleatorios.

Event Date: Nov 15, 2021 in Seminario de Grafos, Seminars

Abstract: Grafos pseudo-aleatorios son grafos deterministas que se comportan como grafos aleatorios en muchos aspectos y su investigación es fundamental para varias áreas de las matemáticas y Ciencias de la Computación. En esta charla daremos una introducción al tema y hablaremos sobre ciclos Hamiltonianos (Krivelevich-Sudakov) y factores triangulares (Nenadov) en tales grafos.

Symmetric positive solutions to nonlinear Choquard equations with potentials.

Event Date: Nov 11, 2021 in Differential Equations, Seminars

Abstract: I will present some existence results for a class of Choquard equations in which the potential has a positive limit at infinity and satisfies suitable decay assumptions. Also, it is taken invariant under the action of a closed subgroup of linear isometries of RN. As a consequence, the positive solution found is invariant under the same action. I will mainly focus on the physical case involving a quadratic nonlinearity. Joint work together with Liliane Maia and Benedetta Pellacci.