Prophet Inequalities Require Only a Constant Number of Samples.

Event Date: May 15, 2024 in ACGO, Seminars

Abstract:  In a prophet inequality problem, n independent random variables are presented to a gambler one by one. The gambler decides when to stop the sequence and obtains the most recent value as a reward. We evaluate a stopping rule by the worst-case ratio between its expected reward and the expectation of the maximum variable. Because of its connections with resource allocation and posted-price mechanisms, this problem has been intensively studied, and several variants have been introduced. While most of the literature assumes that distributions are known to the gambler, recent work has...

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On Wu’s Inequality and the Poisson-Föllmer Process.

Event Date: May 15, 2024 in Seminario de Probabilidades de Chile, Seminars

Resumen:  In the discrete setting the Poisson distribution is a ubiquitous object, as the Gaussian distribution is in the Euclidean setting. In spite of that, it does not satisfy Gross’ log-Sobolev inequality. Nevertheless, Bobkov and Ledoux were able to prove that it satisfies a “modified” version of it, which was subsequently reinforced by Wu. In the first part of this talk we will exhibit a new stochastic proof of Wu’s modified log-Sobolev, via an entropy-minimizing process constructed by Klartag and Lehec, which we call the Poisson-Föllmer process. We will also see how this stochastic...

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Estudio Comparativo De La Evaluación Antropogénica Y Geogénica De La Concentración De Metales Pesados Y Lábiles En Sedimentos Marinos Superficiales Y Suelos De La Zona Norte De Chile.

Event Date: May 23, 2024 in Seminario CMM MIning, Seminars

Resumen: La investigación, permite la identificación, priorización, jerarquización y evaluación preliminar de la contaminación en zonas muy degradadas ambientalmente y posibilita la determinación de los niveles de los cuales se establecen los límites de inocuidad y peligrosidad en ambientes costeros. El propósito del estudio es elaborar un diagnóstico regional de los suelos y sedimentos marinos del borde costero del norte de Chile con potencial presencia de elementos trazas y metales pesados. El estudio, analiza la potencial presencia de 10 metales pesados en el borde costero...

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Coarse Graph Theory I – The Questions

Event Date: May 14, 2024 in Seminario de Grafos, Seminars

Resumen: Coarse graph theory is concerned with the large-scale geometric properties of infinite graphs, especially the properties preserved by quasi-isometries. Although such inquiries have been raised since the 80’s, it was usually in the context of Cayley graphs and geometric group theory. Recently the topic migrated to graph theory with intriguing outcomes. Eventually, the field of coarse graph theory was officially inaugurated and systematically treated in a paper by Georgakopoulos and Papasoglu.   In this talk, I will explain the basics of coarse graph theory, exploreits...

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Formadores de profesores como modelos de enseñanza:¿Qué se sabe al respecto?

Event Date: May 14, 2024 in Seminario de Educación Matemática, Seminars

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A spectral proof of Szemerédi’s regularity lemma.

Event Date: May 07, 2024 in Seminario de Grafos, Seminars

Resumen: In this talk I will present the spectral proof of the regularity lemma due to Frieze and Kannan in the version popularized by Tao.

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