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.

 

A Statistical framework for the modeling of continuous phenotypical progression in Alzheimer’s Disease.

Event Date: Jun 25, 2024 in Seminars

Abstract: Throughout an organism’s life, many biological systems transition through complex biophysical processes. These processes serve as indicators of the underlying biological states. Inferring these latent unobserved states is a key problem in modern biology and neuroscience. Unfortunately, in many experimental setups, we can, at best, obtain snapshots of the system at different times for different individuals, and one major challenge is reconciling those measurements. This formalism is particularly relevant in the study of Alzheimer’s...

Analysis of the survival time of the SIRS process via expansion.

Event Date: Jun 19, 2024 in ACGO, Seminars

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....

A journey through discourses and practices.

Event Date: Jun 17, 2024 in Seminars, SIPo (Seminario de Investigadores Postdoctorales)

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...

Toros exóticos y acciones de SL(d,Z).

Event Date: Jun 17, 2024 in Dynamical Systems, Seminars

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.  

Limiting distributions of Spherical and Spin O(N) models: Appearance of GFF.

Event Date: Jun 12, 2024 in Seminario de Probabilidades de Chile, Seminars

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.

Learning-augmented Assignment: Santa Claus does Load Balancing.

Event Date: Jun 12, 2024 in ACGO, Seminars

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...

Hamiltonicity in pseudorandom graphs: absorbing paths.

Event Date: Jun 11, 2024 in Seminario de Grafos, Seminars

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.

Event Date: Jun 10, 2024 in Dynamical Systems, Seminars

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.

Event Date: Jun 04, 2024 in Seminario de Grafos, Seminars

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.