Noticias en español
Recent progress on tree packings.
Abstract:We say that a graph H decomposes a graph G if the edges of G can be partitioned into edge-disjoint copies of H. In 1976, Ringel conjectured that any tree of order n+1 decomposes the complete graph on 2n+1 vertices. Recently Montgomery, Pokrovskiy and Sudakov presented a proof of this conjecture for large n. In this talk, we will study the techniques used by Montgomery, Pokrovskiy and Sudakov to prove Ringel’s conjecture.
Read MoreMáximo restringido de puentes brownianos no intersectantes.
Resumen: Para un sistema de N puentes Brownianos no intersectantes en [0,1] , se considera M(p,N) la altura máxima alcanzada por el camino superior en el intervalo [0,p] . Bajo un reescalamiento adecuado, M(p,N) converge en distribución, a medida que, N converge a infinito a una familia de distribuciones que interpola entr e las distribuciones de Tracy-Widom para los Ensembles Ortogonales y Unitarios Gaussianos. También se sabe que, para N fijo, M(1,N) se distribuye como el mayor valor propio de una matriz aleatoria extraída del Ensemble Ortogonal de Laguerre. En esta charla se dará una...
Read MoreDistorsión en grupos de difeomorfismos.
Abstract: esta charla discutiremos el concepto de distorsión en grupos. Un elemento de un grupo finitamente generado se dice distorsionado si la métrica de la palabra de sus potencias crece sublineal. Comenzaremos dando una breve introducción, dando un par de ejemplos y luego daremos un par de aplicaciones. Terminaremos planteando y discutiendo una pregunta propuesta por Andrés Navas.
Read MoreLinear and non-linear stability of collisionless many-particle systems on black hole exteriors.
Abstract: I will present upcoming linear and non-linear stability results concerning the asymptotic behavior of collisionless many-particle systems on black hole exteriors. On the one hand, I will discuss decay properties for solutions to the massive Vlasov equation on Schwarzschild spacetime. On the other hand, I will discuss an asymptotic stability result for the exterior of Schwarzschild as a solution to the Einstein–massless Vlasov system, assuming spherical symmetry. I will explain the use of hyperbolic dynamics to obtain decay in time of the energy momentum tensor by considering a...
Read MoreConvergence Rate of Nonconvex Douglas-Rachford splitting via merit functions, with applications to weakly convex constrained optimization.
Abstract: We analyze Douglas-Rachford splitting techniques applied to solving weakly convex optimization problems. Under mild regularity assumptions, and by the token of a suitable merit function, we show convergence to critical points and local linear rates of convergence. The merit function, comparable to the Moreau envelope in Variational Analysis, generates a descent sequence, a feature that allows us to extend to the non-convex setting arguments employed in convex optimization. A by-product of our approach is an ADMM-like method for constrained problems with weakly convex objective...
Read MoreOpening Pandora’s Box: the Correlated Case.
Abstract: Pandora’s Box models optimization problems where the input consists of stochastic random variables, but the uncertainty can be removed (i.e. reveal the exact value of a variable) by paying an extra price. Our goal is to maximize (or minimize) the price of the variable chosen minus (resp. plus) the cost we paid to learn the exact instantiations of the variables. All previous work on this class of problems assumes that different random variables in the input are distributed independently. Until recently nothing was known for the case of correlated input. In this talk I will...
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