Noticias en español
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.
Entropías intermedias y temperatura nula en curvatura negativa
ABSTRACT: Un problema bastante general en teoría ergódica consiste en estudiar al conjunto de entropías de un sistema dinámico respecto a sus medidas ergódicas. Katok conjeturó que dicho conjunto contiene al intervalo $[0,h_{top}(f))$ en el caso de difeomorfismos suaves en variedades compactas. Si bien la conjetura permanece abierta, muchos avances se han logrado a la fecha. Se conoce, por ejemplo, que el flujo geodésico en variedades compactas a curvatura negativa verifica esta propiedad. La demostración de esto último recae en la...
Invariant Random Subgroups of Full Groups of Bratteli diagrams
ABSTRACT: In the talk, we will classify the ergodic invariant random subgroups (IRS) of simple AF full groups. AF full groups arise as the transformation groups of Bratteli diagrams that preserve the cofinality of infinite paths in the diagram. AF full groups are complete (algebraic) invariants for the isomorphism of Bratteli diagrams. Given a simple AF full group G, we will prove that every ergodic IRS of G arises as the stabilizer distribution of a diagonal action on X^n for some n, where X is the path-space of the Bratteli diagram...
A Game Theoretic Model for Optimizing Electricity Consumers Flexibilities in the Smart Grid.
Abstract: With the evolution of electricity usages (electric vehicles, smart appliances) and the development of communication structures (smart grid), new opportunities of optimization have emerged for the actors of the electrical network. Aggregators can send signals to enrolled consumers to play on their demand flexibilities, and to optimize the providing costs and the social welfare. Game theory has been shown to be a valuable tool to study strategic electricity consumers participating in such a demand side management program. We propose a...
On the equitable Hamiltonian Cycle problem
Abstract: Kinable, Smeulders, Delcour, and Spieksma (2017) introduced the Equitable TSP (E-TSP). In the E-TSP, we are given an even number of cities and distances between each pair of these. Instead of finding a tour of minimum length, Kinable et al. (uniquely) decomposed the tour in two perfect matchings, one with “even” edges and one with “odd” edges and the goal is to minimize the difference between the costs of the two perfect matchings. Kinable et al. show that the E-TSP is strongly NP-hard by reduction from Hamiltonian Cycle. The...
Introducción a Percepción Remota y Uso de Satélites SENTINEL
Participación en Línea: http://vcespresso.redclara.net/@352109705c115cdd511fb968f9f4ff86# Use Explorer, Firefox o Safari. Debe tener instalado Flash Player.
Partitioning complete hypergraphs into few monochromatic Berge-cycles
Extending a result of Rado to hypergraphs, we prove that for all r,k with k≥2, the vertices of every r(k-1)-edge-coloured countably infinite complete graph can be core-partitioned into at most r monochromatic Berge-cycles of different colours. We further describe a construction showing that this result is best possible. This is a joint work with Jan Corsten and Nóra Frankl.
Adaptive Computation of Frechet Distance: Upper and Conditional Lower Bound
Abstract: The Fréchet distance is a measure of similarity between curves that takes into account the location and ordering of the points along the curves, and permits to abstract, among other things, differences of resolution between the two curves (with application to morphing, handwriting recognition and protein structure alignment, among others). In 1991, Art and Godau introdued this measure to Computational Geometry, describing an algorithm computing the Fréchet distance between two polygonal curves composed of $n$ and $m$ segments...
Asymptotics for Optimal Transport between N-ples of points, with cost given by electrostatic interaction energy
Abstract: Consider the optimal transport problem N-ples of points, in which the transport cost between N points equals an electrostatic-type energy such as $\sum_{i\neq j} |x_i-x_j|^{-s}$ with $0<s<d$. We are led to a minimization problem for probability measures on $(\mathbb R^d)^N$, which is an N-marginal Optimal Transport problem, and has a direct physical interpretation. We prove the sharp large-N asymptotics for the above N-marginal transport problem at second order, namely beyond the mean-field continuum limit. To this aim we...
On the current-current correlation measure for random Schrödinger operators
Abstract: We review various properties of random Schrödinger operators and recall formulations of conductivity and current-current correlation measure. In this talk we will present a panoramic view and recent results on localized regime. We will focus in particular on the diagonal behaviour problem of the ccc-measure and explain how it is related to the localization length. This is a work in progress with J. Bellissard and G. De Nettis.
Lower Bounds for Online Matching on the Line
Abstract: In the online matching on the line problem, the task is to match a set of requests R online to a given set of servers S. The distance metric between any two points in R ∪ S is a line metric and the objective for the online algorithm is to minimize the sum of distances between matched server-request pairs. This problem is well-studied and – despite recent improvements – there is still a large gap between the best known lower and upper bounds: The best known deterministic algorithm for the problem is O(log^2(n))-competitive, while the...
