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.
Analysis of the survival time of the SIRS process via expansion.
Abstract: We study the SIRS process—a continuous-time Markov chain modelling thespread of infections on graphs. In this model, vertices are eithersusceptible, infected, or recovered. Each infected vertex becomesrecovered at rate 1 and infects each of its susceptible neighbors independently at rate~$\lambda$, and each recovered vertex becomes susceptible at a rate~$\rho$, which we assume to be independent of the graph size. A central quantity of the SIRS process is the time until no vertex is infected, known as the survival time....
Toros exóticos y acciones de SL(d,Z).
RESUMEN: Una de las características más distintivas del toro d-dimensional (i.e. el producto de d círculos) T^d es que admite una acción C-infinito efectiva del grupo SL(d,Z) de matrices d x d con entradas enteras. Uno podría preguntarse si una acción así (o cualquier acción no trivial) también existe sobre toros exóticos, es decir, variedades diferenciables que son homeomorfas pero no difeomorfas a T^d. En mi charla, luego de revisar algunas generalidades sobre variedades exóticas, voy a discutir esta pregunta.
A journey through discourses and practices.
Summary: Our experiencing and, thus, our practices are co-enabled by entwined fields of knowledge, fields of power and forms of subjectivity. Through the articulation of different research pieces, and one protagonist, in this SIPo session we will tackle the following question: how free are we? Our protagonist is a student enrolled in Chile’s Secondary Technical VocationalEducation and Training (S-TVET) system. All research pieces used to drive then narrative of the presentation are the result of a postdoctoral research endeavor. These...
Learning-augmented Assignment: Santa Claus does Load Balancing.
Abstract: Assignment problems are among the most well-studied in online algorithms. In these problems, a sequence of items arriving online must be assigned among a set of agents so as to optimize a given objective. This encompasses scheduling problems for minimizing makespan, p-norms, and other objectives, as well as fair division problems such as the Santa Claus problem and Nash welfare maximization. One common feature is that many of these problems are characterized by strong worst-case lower bounds in the online setting. To circumvent...
Limiting distributions of Spherical and Spin O(N) models: Appearance of GFF.
Resumen: Spherical model is a mathematical model of a ferromagnet introduced by Berlin and Kac in 1952 as a rough but analytically convenient modification of the Ising model. Since its inception it has enjoyed considerable popularity among the mathematicians and physicists as an exactly soluble model exhibiting a phase transition. In this talk we will explain its relation to the Gaussian free field in the infinite volume limit and to the spin O(N) model in the infinite spin-dimensionality limit of the latter.
Hamiltonicity in pseudorandom graphs: absorbing paths.
Abstract: In this second talk, we will introduce the “extendability method” for embedding sparse structures in expander graphs and we will use it to construct efficient absorbers to solve the Hamiltonicity problem in pseudorandom graphs.
Decaimiento de correlaciones para ciertos atractores no uniformemente hiperbólicos.
RESUMEN: Un problema clásico en sistemas dinámicos es conocido como el problema de realización, el cual consiste en preguntar si dada una variedad compacta M, uno puede construir un difeomorfismo en M con ciertas propiedades ergódicas. Vamos a estudiar el decaimiento de correlaciones para ciertos sistemas dinámicos no uniformemente hiperbólicos con respecto a su medida SRB. El sistema g que vamos a considerar se obtiene de un difeomorfismo uniformemente hiperbólico f al que se le aplica el procedimiento de desaceleración. Bajo ciertas...
Hamiltonicity in pseudorandom graphs: Pósa rotation.
Abstract: In this series of talks, we will study different approaches to the Hamiltonicity problem in sparse pseudorandom graphs. In this first talk, we will review the celebrated “extension-rotation” technique pioneered by Pósa in the 70s and how to use it in pseudorandom graphs to find Hamilton cycles.
Problemas Respecto a la Invarianza del Espectro de Dicotomia No Uniforme.
RESUMEN: En su tesis doctoral, S. Siegmund demostró que si dos sistemas eran cinemáticamente similares, entones tenían el mismo espectro de dicotomía exponencial. En los ultimos años se han propuesto muchas generalizaciones a este resultado para abarcar las dicotomias no uniformes. En esta charla demuestro que estas generalizaciones no se siguen realmente, ya que se basan en hipótesis que no se alcanzan de manera general. Junto con ello, presento ejemplos explícitos y además propongo una alternativa más débil de la invarianza espectral,...
