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.

 

On large solutions for fractional Hamilton-Jacobi equations.

Event Date: Aug 25, 2022 in Differential Equations, Seminars

Abstract: In this talk I will report some multiplicity results for large solutions of fractional Hamilton-Jacobi equations posed on a bounded domain, subject to exterior Dirichlet conditions. We construct large solutions using the method of sub and supersolutions, following the classical approach of J.M. Lasry and P.L. Lions for second-order equations with subquadratic gradient growth. We identify two classes of solutions: the one coming from the natural scaling of the problem; and a one-parameter family of solutions, different from the...

A multiple time renewal equation for neural assemblies with elapsed time model.

Event Date: Aug 23, 2022 in Differential Equations, Seminars

Abstract: We introduce and study an extension of the classical elapsed time equation in the context of neuron populations that are described by the elapsed time since last discharge. In this extension we incorporate the elapsed since the penultimate discharge and we obtain a more complex system of integro-differential equations. For this new system we prove convergence to stationary state by means of Doeblin’s theory in the case of weak non-linearities in an appropriate functional setting, inspired by the case of the classical elapsed...

Árboles generadores en grafos densos I.

Event Date: Aug 18, 2022 in Seminario de Grafos, Seminars

Abstract: Dados dos grafos H y G un problema central en teoría de grafos extremales es determinar condiciones globales en G que garantizan la existencia de una copia de H en G. Un ejemplo de resultado en esa dirección es el Teorema de Dirac, que afirma que si G es un grafo en nvértices con grado mínimo al menos n/2, entonces existe una copia del ciclo en n vértices en G. En este seminario vamos a estudiar la relación entre el grado mínimo de G y la existencia de copias de diferentes árboles generadores de G. Más específicamente, vamos a...

A random walk in Number Theory.

Event Date: Aug 17, 2022 in Seminario de Probabilidades de Chile, Seminars

Abstract:  Ver pdf 

Prophet Inequalities via the Expected Competitive Ratio.

Event Date: Aug 17, 2022 in ACGO, Seminars

Abstract: We consider prophet inequalities under general downward-closed constraints. In a prophet inequality problem, a decision-maker sees a series of online elements and needs to decide immediately and irrevocably whether or not to select each element upon its arrival, subject to an underlying feasibility constraint. Traditionally, the decision-maker’s expected performance has been compared to the expected performance of the prophet, i.e., the expected offline optimum. We refer to this measure as the Ratio of Expectations (or, in short,...

On the fractional Zakharov-Kuznetsov equation.

Event Date: Aug 16, 2022 in Differential Equations, Seminars

Abstract: In this talk, we will present some new results related to the regularity properties of the initial value problem (IVP) for the equation” Bt u ́ Bx1 ( ́∆)α/2u + uBx1 u = 0, 0 ă α ă 2, u(x, 0) = u0(x), x = (x1, x2, . . . , xn ) P Rn, n ě 2, t P R, (0.1) where ( ́∆)α/2 denotes the n ́dimensional fractional Laplacian. In the particular case that α= 2, the equation is known as the Zakharov-Kuznetsov-(ZK) equation and it was proposed by Zakharov and Kuznetsov as amodel to describe the propagation of ion-sound waves in magnetic...

Trayectorias de aprendizaje y perfiles de conocimientos matemáticos de los candidatos a docentes al ingresar a la formación inicial.

Event Date: Aug 09, 2022 in Education, Seminars

RESUMEN En la selección de candidatos para ingresar a los programas de formación inicial docente se ha puesto énfasis en la medición de conocimientos disciplinares y pedagógicos mediante metodologías psicométricas que solo ordenan a los candidatos en escalas continuas. Esto no permite identificar perfiles y/o trayectorias de aprendizaje que faciliten la creación de procesos de acompañamiento en los programas de formación y con ello alcanzar perfiles de egreso deseados. Así, aplicando el modelo psicométrico de clasificación...

p-harmonic functions with Neumann conditions and measure data.

Event Date: Aug 09, 2022 in Differential Equations, Seminars

Abstract: In this talk I will discuss the problem of finding solutions to some nonlinear elliptic equations with measure data. To this end I will introduce the concept of Renormalized Solutions, which is a very useful tool to solve both Dirichlet and Neumann problems. I will present some results in this area and also discuss some open problems.