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.
Invariant measures of discrete interacting particle systems: Algebraic aspects
Abstract: We consider a continuous time particle system on a graph L being either Z, Z_n, a segment {1,…, n}, or Z^d, with state space Ek={0,…,k-1} for some k belonging to {infinity, 2, 3, …}. We also assume that the Markovian evolution is driven by some translation invariant local dynamics with bounded width dependence, encoded by a rate matrix T. These are standard settings, satisfied by many studied particle systems. We provide some sufficient and/or necessary conditions on the matrix T, so that this Markov process admits some...
Markets and Fair Division of Goods
Abstract: Items have to be distributed to agents in a fair manner. The agents have valuations for the goods and the value of a set of goods is simply the sum of the valuations. Nash introduced axioms for fairness and showed that for divisible goods maximizing the product of the agent’s valuations leads to a fair division. The allocation maximizing the product is the same as the allocation in a Fisher market in which all agents have the same budget. For indivisible goods the problem is harder. Cole/Gkatzelis gave an approximation algorithm...
Robust Submodular Maximization: Offline and Online algorithms
Abstract: In this work, we consider the robust submodular maximization problem subject to a matroid constraint in the offline and online setting. In the offline version, we are given a collection of k monotone submodular functions and matroid on a ground set of size n. The goal is to select one independent set that maximizes the minimum of the submodular functions. Given the complexity of the problem, we design a bi-criteria approximation algorithm that returns a set that is the union of a logarithmic number of independent sets. In the online...
A priori estimates for elliptic equations in $\mathbb R^N$ – a critical case
Abstract: Using the Moser’s iteraction method we obtain an a priori estimate for elliptic equations in whole euclidian space in a critical growth situation
Projected solutions for quasi-equilibrium problems.
Abstract: In 2016, Aussel, Sultana and Vetrivel introduced the concept of projected solutions for generalized Nash equilibrium problems (GNEPs)in the finite dimensional case. To show the existence of such solutions they studied projected solutions for quasi-variational inequality problems. In a similar spirit, we introduce the concept of projected solution for quasi-equilibrium problems (QEPs). As a consequence of our main result we obtain an existence result for projected solutions of GNEPs, in infinite dimensional spaces....
Empoderar a grupos de trabajo en el aula: Una obligación que guía a los profesores de matemática en instituciones de acceso abierto en Chile
Resumen: Este estudio aborda cómo las interacciones entre profesores y grupos de trabajo se relacionan con las prácticas en sala y la toma de decisiones en la enseñanza de la matemática en instituciones de acceso abierto, en educación superior. Definimos las interacciones entre profesores y grupos de estudiantes desde el momento en que el profesor visita un grupo que trabaja en una tarea matemática específica, que en nuestro caso corresponden a actividades de resolución de problemas. La metodología es mixta y basada en dos conjuntos de...
Construction of geometric rough paths
Abstract: This talk is based on a joint work in progress with L. Zambotti (UPMC). First, I will give a brief introduction to the theory of rough paths focusing on the case of Hölder regularity between 1/3 and 1/2. After this, I will address the basic problem of construction of a geometric rough path over a given ɑ-Hölder path in a finite-dimensional vector space. Although this problem was already solved by Lyons and Victoir in 2007, their method relies on the axiom of choice and thus is not explicit; in exchange the proof is simpler....
3 SESIONES SEMINARIO OPTIMIZACION Y EQUILIBRIO
Expositores 16:00–16:30hrs Prof. Boulmezaoud, Tahar Zamene, Laboratoire de Mathématiques de Versailles, Université de Versailles, France Title: On Fourier transform and weighted Sobolev spaces Astract: We prove that Fourier transform defines a simple correspondance between weighted Sobolev spaces. As a consequence, we display a chain of nested invariant spaces over which Fourier transform is an isometry. &&&&& 16:30–17:00 hrs Prof. Lev Birbrair, Federal Univerisity of Ceara, Brazil Title: Resonance sequences. ...
Limits of sequences of maximal monotone operators.
Abstract: We consider a sequence of maximal monotone operators on a reflexive Banach space. In general, the (Kuratowski) lower limit of such a sequence is not a maximal monotone operator. So, what can be said? In the first part of the talk, we show that such a limit is a representable monotone operator while its Mosco limit, when it exists, is a maximal monotone operator. As an application of the former result, we obtain that the variational sum of two maximal monotone operators is a representable monotone operator. In the second part of the...
Existence results for equilibrium problem
Abstract: In this paper, we introduce certain regularizations for bifunctions, based on the corresponding regularization for functions, originally defined by J-P. Crouzeix. We show that the equilibrium problems associated to a bifunction and its regularizations are equivalent in the sense that they share the same solution set. Also, we introduce new existence results for the Equilibrium Problem, and we show some applications to minimization and Nash equilibrium problems.
