Noticias en español
Single-choice secretary problems with ordinal advice.
Abstract: We examine variations of the classical secretary problem in a new setting, where the decision-maker (DM) can request one (or more) bits of ordinal information from agents before they arrive. Specifically, each agent has private information (their weight) that is publicly revealed upon arrival. As usual, the DM must irrevocably decide whether to select the agent or not after this step. Additionally, at any given time, the DM can privately ask yes-or-no questions to agents who have not yet arrived, and the agents can only answer ordinal questions based on comparing their private...
Read MoreLipschitz regularity of almost minimizers for a degenerate one-phase Bernoulli-type functional.
Abstract: In this talk, we deal with almost minimizers for the energy functional (,Ω):=∫Ω(|∇()|+{>0}()),>1,(1) where Ω is a bounded domain in ℝ and ≥0. The functional is a generalization to each >1 of the classical one-phase (Bernoulli) energy functional, corresponding to =2 in (1). Almost minimizers of 2 were investigated recently in [2, 1]. However, in [4] D. De Silva and O. Savin provided a different approach with respect to [2, 1], based on nonvariational techniques, to deal with almost minimizers of 2 and their free boundaries. Precisely, inspired by [5], they showed...
Read MoreConversaciones entre la teoría de modelos y la teoría de grafos.
Abstract: En esta charla se pretende mostrar la utilidad de la teoría de modelos en combinatoria. En concreto, en la obtención de resultados para grafos infinitos. Se comenzará introduciendo el concepto de modelo para un lenguaje con una signatura dada, el concepto de submodelo y submodelo elemental, subrayando sus diferencias mediante un ejemplo. Posteriormente, se expondrá la construcción de submodelos elementales como herramienta para obtener resultados en grafos infinitos, en concreto para mostrar que si un grafo no tiene ningún corte mínimo impar, y pertenece a un modelo M para el cual...
Read MoreLearning in scheduling: simple policies for Bayesian scheduling.
Abstract: We consider the problem of scheduling jobs on a single machine, non-preemptively. The goal is to minimize the total completion time of the jobs. It is well known that this problem is solved by scheduling the jobs in order of shortest processing times (SPT) when the jobs’ processing times are known or shortest expected processing times (SEPT), when we have full knowledge on the true expected values. In this talk, we consider the stochastic scheduling problem in which we have additional uncertainty about the parameters of the distribution of the jobs’ processing times. We assume that...
Read More(Near-)critical percolation with long-range correlations on transient graphs .
Abstract: Percolation models have been playing a fundamental role in statistical physics for several decades by now. They had initially been investigated in the gelation of polymers during the 1940s by chemistry Nobel laureate Flory and Stockmayer. From a mathematical point of view, the birth of percolation theory was the introduction of Bernoulli percolation by Broadbent and Hammersley in 1957, motivated by research on gas masks for coal miners. One of the key features of this model is the inherent stochastic independence which simplifies its investigation, and which has lead to deep...
Read MoreCaracterización de flujos estrella en dimensión baja y alta.
RESUMEN En difeomorfismos, la hiperbolicidad estable de las órbitas periódicas en la topología C^1 es equivalente a la hiperbolicidad/ estabilidad en el conjunto de las órbitas recurrentes. Esto permite entender la dinámica de un sistema a través del comportamiento de sus órbitas periódicas. Para flujos con singularidades, obtener una estructura hiperbólica o parcialmente hiperbólica ha demostrado ser más difícil y aún no está completamente cerrado aún, a pesar de numerosísimas contribuciones. En esta charla daremos un panorama sobre las estructuras hiperbólicas o parcialmente hiperbólicas...
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