Seminars

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.

 

CURTIS-HEDLUND-LYNDON THEOREM FOR ULTRAGRAPH SHIFT SPACES

Event Date: Jan 22, 2018 in Dynamical Systems, Seminars

ABSTRACT: In this work we characterize the class of continuous shift commuting maps between ultragraph shift spaces, proving a Curtis-Hedlund-Lyndon type theorem. Then we use it to characterize continuous, shift commuting, length preserving maps in terms of generalized sliding block codes. This is a joint work with Prof. Daniel Gon\c{c}alves (UFSC, Brazil)

Optimal transport and applications to Data Science

Event Date: Jan 17, 2018 in Seminario Aprendizaje de Máquinas, Seminars

Abstract: Optimal transport (OT) provides rich representations of the discrepancy between probability measures supported on geometric spaces. Recently, thanks to the development of computational techniques, OT has been used to address problems involving massive datasets, as an alternative to usual KL-divergence based approaches. In this talk I will introduce the OT problem and comment on its elementary duality properties. Then, I will present the entropy regularized problem and its (fast) solution via Sinkhorn iterations. Finally, I will...

Projected solutions of quasi-variational inequalities with application to bidding process in electricity market

Event Date: Jan 17, 2018 in Optimization and Equilibrium, Seminars

Abstract:   Quasi-variational inequalities provide perfect tools  to reformulate Generalized Nash Equilibrium Probem (GNEP), the latter being a good model to describe the day-ahead  electricity markets.   Our aim in this talk is to illustrate how some recent advances in the theory  of quasi-variational inequalities can influence the modeling of electricity market.   Talk based on: – D. Aussel, A. Sultana & V. Vetrivel, On the existence of projected solutions of quasi-variational inequalities and generalized Nash...

Physics-based Models for Uncertainty Quantification in Chemical Kinetics

Event Date: Jan 15, 2018 in Seminario Aprendizaje de Máquinas, Seminars

Abstract:   Prediction is a core element of science and engineering. Sophisticated mathematical models exist to make predictions in a variety of physical contexts including materials science, fluid mechanics, and solid mechanics. Most of these models do not have known analytical solutions. Moreover, they are generally difficult to solve numerically. In order to perform numerically tractable computations, researchers often try to develop reduced models that account for the essential physics while doing away with the complexity of the full...

Invariant measures of discrete interacting particle systems: Algebraic aspects

Event Date: Jan 09, 2018 in Núcleo Modelos Estocásticos de Sistemas Complejos y Desordenados, Seminars

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...

Projected solutions for quasi-equilibrium problems.

Event Date: Dec 06, 2017 in Optimization and Equilibrium, Seminars

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

Event Date: Dec 06, 2017 in Education, Seminars

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

Event Date: Nov 27, 2017 in Núcleo Modelos Estocásticos de Sistemas Complejos y Desordenados, Seminars

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

Event Date: Nov 22, 2017 in Optimization and Equilibrium, Seminars

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.

Event Date: Nov 15, 2017 in Optimization and Equilibrium, Seminars

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...