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Dr. Nelda Jaque at University of Chile gave the talk “Topological entropy for discontinuous semiflows" at our seminar.
 Sep 25, 2020

Dr. Nelda Jaque presented an example of a discontinuous semiflow acting on a compact metric space. It also showed variations in Bowen's definitions of topological entropy, applied to the study of discontinuous semiflows on compact metric spaces.

Professor Gareth A. Jones at University of Southampton gave the talk “Automorphism groups of Riemann surfaces and dessins d’enfants" at our seminar.
 Sep 11, 2020

On this opportunity, Professor Dr. Jones gave a short and explicit algebraic proof of Greenberg’s Theorems for finitely generated groups, using results of Macbeath, Singerman and Takeuchi on triangle groups, and of Margulis on arithmeticity. In each case, a Riemann surface S is a quotient of the hyperbolic plane by an explicit subgroup of a triangle group. When the group is finite it follows from this and from Belyi’s Theorem that the surface can be defined, as a complex algebraic curve, over an algebraic number field.

Dr. Pedro Gajardo at Federico Santa María Technical University gave the talk “Sustainable thresholds: A focus from control theory for reconciling opposing goals" at our seminar.
 Sep 04, 2020

On this occasion, Dr. Gajardo presented various interpretations of the set of sustainable thresholds, their advantages over the feasibility core and applications for fisheries management and epidemic control. Dr. Gajardo has led several national grants that have contributed to the improvement of the quality of life of workers in the fishing sector.

Dr. Jennifer Paulhus at Grinnel Collegue, USA, gave the talk "Automorphism Groups of Riemann Surfaces" at our seminar.
 Aug 7, 2020

On this occasion, Dr. Paulhus gave an introduction to Riemann surfaces and their automorphism groups, focusing on the algebraic side. Dr. Paulhus also presented some recent advances of her research on these automorphisms, as well as applications to Jacobian varieties.

Dr. Alexander Quaas at Federico Santa María Technical University, Valparaíso, Chile, gave the talk "The sharp exponent in the study of the nonlocal Hénon equation in ℝ^N. A Liouville theorem and an existence result" at our seminar.
 Jul 31, 2020

In this opportunity, Dr. Quaas presented problems with non local diffusion involving the fractional Laplacian operator and other integro-differential operators. These appear when trying to model different physical situations such as anomalous diffusion, quasi-geostrophic flows, water waves, among others.

Luis Sánchez successfully defended his thesis “Birnbaum-Saunders quantile regression models”
 Jul 30, 2020

Dr. Sánchez defended his Doctoral thesis last July 30th. His thesis was supervised by professor Dr. Víctor Leiva. The jury was composed of professors Dr. Helton Saulo (University of Brasilia, Brazil), and Dr. Manuel Galea (Pontifical Catholic University of Chile).

Dr. Giancarlo Lucchini at University of Chile, gave the talk "On extensions of algebraic groups" at our seminar.
 May 20, 2020

In this talk, Dr. Lucchini gave two proofs of a relationship between the set Ext(G,H) of isomorphism classes of extensions of a group G by a group H and Ext(G,Z), where Z is the center of H. The new proof allows for a direct extension of the result to the context of algebraic groups. Joint work with Mathieu Florence.