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.

 

The group of reversible Turing machines and the torsion problem for $\Aut(A^{\mathbb{Z})$ and related topological fullgroups.

Event Date: Dec 19, 2016 in Dynamical Systems, Seminars

Abstract:   We introduce the group $RTM(G,n,k)$ composed of abstract Turing machines which use the group $G$ as a tape, use an alphabet of $n$ symbols, $k$ states and act as a bijection on the set of configurations. These objects can be represented both as cellular automata and in terms of continous functions and cocycles. The study of this group structure yields interesting results concerning computability properties of some well studied groups such as $\Aut(A^{\mathbb{Z})$ and the topological full group of the two dimensional full shift....

Iterative regularization via a dual diagonal descent method

Event Date: Dec 14, 2016 in Optimization and Equilibrium, Seminars

   Abstract: In the context of linear inverse problems, we propose and study general iterative regularization method allowing to consider classes of regularizers and data-fit terms. The algorithm we propose is based on a primal-dual diagonal descent method, designed to solve hierarchical optimization problems. Our analysis establishes convergence as well as stability results, in presence of error in the data. In this noisy case, the number of iterations is shown to act as a regularization parameter, which makes our algorithm an iterative...

Seguimiento docente e implementación de recursos educativos de Comunidad inGenio en el aula

Event Date: Dec 13, 2016 in Education, Seminars

Resumen: La exposición abordará el proyecto “Seguimiento Docente”, el cual consiste en una serie de actividades y trabajo de capacitación con diversos profesores de matemática de enseñanza media en la R.M. y Biobío. Este proyecto es desarrollado por Comunidad InGenio, programa de divulgación y educación del Instituto Sistemas Complejos de Ingeniería (ISCI). Con más de 8 años de experiencia, Comunidad InGenio cuenta con una variedad de recursos educativos basados en la investigación científica que el ISCI desarrolla. De esta manera, y a través...

Propagation of critical behavior for unitary invariant plus GUE random matrices

Event Date: Nov 24, 2016 in Núcleo Modelos Estocásticos de Sistemas Complejos y Desordenados, Seminars

Abstract: It is a well known and celebrated fact that the eigenvalues of random Hermitian matrices from a unitary invariant ensemble form a determinantal point process with correlation kernel given in terms of a system of orthogonal polynomials on the real line. It is a much more recent result that the eigenvalues of the sum of such a random matrix with a matrix from the Gaussian unitary ensemble (GUE) also forms a determinantal point process, with the kernel given in terms of the Weierstrass transform of the original kernel. I’ll talk about...

Does convexity arise in optimization naturally?

Event Date: Nov 16, 2016 in Optimization and Equilibrium, Seminars

Abstract Convexity is one of the conditions that any researcher may desire to have when dealing with problems in Optimization. Thus, the lack of standard convexity provides an interesting challenge in mathematics. In this talk we show various instances from mathematical programming, differential inclusions to calculus of variations, where convexity is present in one way or in another. Among the issues to be described lie: strong duality, KKT optimality conditions; joint-range and the S-lemma for a pair of (not necessarily homogeneous)...

Relación de las mujeres con las matemáticas: La necesidad de un modelo multinivel y múltiples métodos de investigación.

Event Date: Nov 15, 2016 in Education, Seminars

Resumen: La relación ‘complicada’ de las mujeres con las matemáticas ha sido un área de profunda investigación ya por mas de 40 años. En esta presentación recorreremos los principales modelos teóricos que han sido utilizados para comprender esta situación y revisaremos una propuesta integrativa que pone al sujeto (y sus identidades – particularmente su ‘identidad matemática’) en el centro de la indagación. Usando este modelo exploraremos algunas preguntas de mi tesis doctoral: ¿Qué tan grande son las diferencias de rendimiento? ¿Existe una...

Shearer’s inequality and the Infimum Rule

Event Date: Oct 25, 2016 in Seminars, Stochastic Modeling

 Abstract: We review subbadditivity properties of Shannon entropy, in particular, from the Shearer’€™s inequality we derive the €œinfimum rule†for actions of amenable groups. We briefly discuss applicability of the €œinfimum formula to actions of other groups. Then we pass to topological entropy of a cover. We prove Shearer’€™s inequality for disjoint covers and give counterexamples otherwise. We also prove that, for actions of amenable groups, the supremum over all open covers of the €œinfimum fomula gives correct value of...

New techniques for pressure approximation in Z^d shift spaces

Event Date: Oct 19, 2016 in Dynamical Systems, Seminars

ABSTRACT:   Given a Z^d shift of finite type and a nearest-neighbour interaction, we present sufficient conditions for efficient approximation of pressure and, in particular, topological entropy. Among these conditions, we introduce a combinatorial analog of the measure-theoretic property of Gibbs measures known as strong spatial mixing. The approximation techniques make use of a special representation theorem for pressure that may be of independent interest. Part of this talk is joint work with Stefan Adams, Brian Marcus, and Ronnie...

On the Convergence of Projection Method for Co-coercive Variational Inequalities

Event Date: Oct 19, 2016 in Optimization and Equilibrium, Seminars

Abstract: We revisit the basic projection method for solving co-coercive  variational inequalities in real Hilbert spaces. The weak and the strong convergence for the  iterative sequences generated by this method are studied. We also propose several examples to analyze  the obtained results. This is a joint work with Phan Tu Vuong.