Seminars

Extension Complexity.

Event Date: Sep 12, 2018 in AGCO, Seminars

Abstract: A polytope Q is called an extension of a polytope P if P is a projection of Q. The extension complexity of a polytope is the minimum number of inequalities needed to describe any of its extensions. In this talk I will describe some results related to extension complexities of several important polytopes arising in combinatorial optimization and discuss how extension complexity can be used to model computational difficulty of solving problems.

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Strong Algorithms for the Ordinal Matroid Secretary Problem

Event Date: Sep 05, 2018 in AGCO, Seminars

Abstract: A general technique and analysis for the matroid secretary problem is presented and then we show how to achieve a 4-competitive algorithm for the case of graphic matroids.

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Minicurso Mating of trees a cargo de Avelio Sepulveda (Université Lyon 1).

Event Date: Sep 03, 2018 in Seminars

Mating of trees: una aproximación discreta.   El objetivo de este mini-curso es introducir ciertos modelos canónicos de espacios métricos aleatorios discretos y obtener sus límites continuos. Para ello comenzaremos analizando los árboles aleatorios y probando su convergencia al CRT (continuous random tree). Luego, definiremos las cartas aleatorias uniformes ( uniform random planar maps) y estudiaremos su  convergencia como espacio métrico y cómo esta convergencia se relaciona con ciertos árboles contenidos en la carta. Finalmente, introduciremos la biyección Hamburguer-Cheeseburguer,...

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El potencial de los satélites para estudiar y monitorear eventos hidrometeorológicos extremos.

Event Date: Sep 03, 2018 in Ciclo de Seminarios quincenales de la Alianza Copernicus-Chile, Seminars

Seminarios de la Alianza Copernicus-Chile Titulo El potencial de los satélites para estudiar y monitorear eventos hidrometeorológicos extremos. Expositor Roberto Rondanelli, U. de Chile Sala:  Sala Multimedia, Centro de Modelamiento Matemático, Beauchef 851, Edificio Norte, Piso 6. Fecha:  Lunes 03 de Septiembre de 2018 Hora:  16:00 horas Participación en Linea:...

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A (5/3 + ε)-Approximation for Unsplittable Flow on a Path: Placing Small Tasks into Boxes

Event Date: Aug 29, 2018 in AGCO, Seminars

Abstract:  In the unsplittable flow on a path problem (UFP) we are given a path with edge capacities and a collection of tasks. Each task is characterized by a subpath, a profit, and a demand. Our goal is to compute a maximum profit subset of tasks such that, for each edge e, the total demand of selected tasks that use e does not exceed the capacity of e. The current best polynomial-time approximation factor for this problem is 2 + eps for any constant eps>0. This is the best known factor even in the case of uniform edge capacities. These results, likewise most prior work, are based on a...

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SEMINAR CAPDE de EDPs

Event Date: Sep 03, 2018 in CAPDE, Seminars

SEMINAR CAPDE de EDPs   Primera Sesión 16:00 hs. Expositor Panayotis Smyrnelis DIM-CMM Universidad de Chile   Title Minimal heteroclinics for second and fourth order O.D.E systems   Segunda Sesión 17:00 hrs.   Expositor Chulkwang Kwak (PUC)   Title Well-posedness issues of some dispersive equations under the periodic boundary condition.   Abstract: In this talk, we are going to discuss about the well-posedness theory of dispersive equations (KdV- and NLS-type equations) posed on T, via analytic methods. I am going to briefly explain some notions and methodologies required to study the...

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