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.
Joint ergodicity beyond polynomials
RESUMEN: In this talk we will present recent joint ergodicity results for various non-polynomial functions of polynomial growth. We will mention the historical context of the question, and the techniques we use, which combine recent works of Frantzikinakis and Tsinas with the machinery of seminorms for multiple averages for polynomial iterates that we have developed in a previous work with A. Ferre-Moragues, A. Koutsogiannis, and W. Sun. If time permits, we will provide comments on open questions and current ongoing work. This is joint work...
New mathematical model for Tsunamis with precise time arrival predictions.
Abstract: We propose in this work a new system of equations modeling Tsunamis. It is a coupled system accounting for both water compressibility and viscoelasticity of the earth. Adding these latter physical effects is responsible for the closest-to-reality time arrival predictions (among existing models), capturing the negative peak before the main wave hump, and the exhibition of the negative dispersion phenomena. This comes in remarkable agreement with previous experiments and studies on the topic. The system is also delivered in a...
Energy-Efficient Distributed Algorithms for Synchronous Networks.
Abstract: We study the design of energy-efficient algorithms for well known distributed models of computation: the LOCAL and CONGEST models. Specifically, as a measure of complexity, we consider the maximum, taken over all the edges, or over all the nodes, of the number of rounds at which an edge, or a node, is activein the algorithm. We first show that every Turing-computable problem has a CONGEST algorithm with constant node-activation complexity, and therefore constant edge-activation complexity as well. That is, every node (resp., edge)...
Construcción lookdown a un modelo Moran con Banco de semillas.
Abstract: En esta plática abordaremos un trabajo en conjunto con M.C. Fittipaldi (FC,UNAM) y A. Gonzáles Casanova (IMATE, UNAM, UC, Berkeley) en el cual estudiamos una representación alterna al modelo de Moran con Banco de semillas. Se mostrará que bajo la misma distribución inicial intercambiable ambos modelos son iguales en ley. Dicha construcción nos permitirá profundizar en el estudio del tiempo hasta el ancestro en común de una muestra de individuos (TMRCA). Adicionalmente traduciremos este resultado en el tiempo de fijación de un...
In this apportionment lottery, the House always wins.
Abstract Apportionment is the problem of distributing h indivisible seats across states in proportion to the states’ populations. In the context of the US House of Representatives, this problem has a rich history and is a prime example of interactions between mathematical analysis and political practice. Grimmett suggested to apportion seats in a randomized way such that each state receives exactly their proportional share qᵢ of seats in expectation (ex ante proportionality) and receives either ⌊qᵢ⌋ or ⌈qᵢ⌉ many seats ex post (quota)....
On the collapse of the local Rayleigh condition for the hydrostatic Euler equations.
Abstract: The hydrostatic Euler equations are derived from the incompressible Euler equations by means of the hydrostatic approximation. Among the different stability criteria that arise in the study of linear stability for the incompressible Euler equations, we can mention Rayeligh’s stability criterion, which gives rise to the local Rayleigh condition. Linear and nonlinear instability of the hydrostatic Euler equations around certain shear flows is well-known, as well as the finite time blow-up of certain solutions that do not satisfy...
Condiciones de grado mínimo para caminos y ciclos monocromáticos en grafos 2-arista-coloreados (segunda parte).
Abstract: Diremos que un grafo $G$ apunta a un grafo $H$ si es que en cada $2$-arista-coloreo de $G$ existe una copia monocromática de $H$. Schelp tenía la idea de que si el grafo completo $K_n$ apunta un grafo pequeño $H$, entonces cada subgrafo denso de $K_n$ también apunta a H.En este seminario, veremos un resultado demostrado por Balogh, Kostochka, Lavrov y Liu en 2021 ( https://arxiv.org/pdf/1906.02854.pdf ) que indica que “para todo $n$ suficientemente grande, si $n = 3t + r$ donde $r\in\{0,1,2\} y $G$ es un grafo en $n$ vértices...
The IID Prophet Inequality with Limited Flexibility.
Abstract: In online sales, sellers usually offer each potential buyer a posted price in a take-it-or-leave fashion. Buyers can sometimes see posted prices faced by other buyers, and changing the price frequently could be considered unfair. The literature on posted price mechanisms and prophet inequality problems has studied the two extremes of pricing policies, the fixed price policy and fully dynamic pricing. The former is suboptimal in revenue but is perceived as fairer than the latter. This work examines the middle situation, where there...
Marchas aleatorias activadas críticas.
Resumen: El modelo de marchas aleatorias activadas (Activated Random Walks, ARW) es un sistema de partículas introducido con el fin de estudiar la criticalidad auto-organizada. Este consiste en una familia de partículas que se mueven aleatoriamente y que pueden dormirse espontáneamente, lo que detiene el movimiento. La interacción ocurre cuando una partícula activa visita a una durmiendo, lo que gatilla que la partícula dormida se active y continúe su movimiento. Este modelo presenta una transición de fase en términos de la densidad de...
Trayectorias de Procesos Geométricos en edades iniciales: análisis de oportunidades de aprendizaje en textos escolares
Resumen: El texto escolar se puede comprender como parte del currículum potencial por lo que en esta presentación se mostrarán los resultados de un estudio exploratorio sobre cuáles son los procesos geométricos presentes en las oportunidades de aprendizaje creadas para libros de texto chilenos de educación Matemática inicial. El análisis de las experiencias de aprendizaje se realizó por medio de una adaptación de las trayectorias de aprendizaje, identificando procesos geométricos y sus indicadores para las categorías temáticas de Forma,...
