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.
Árboles generadores en grafos densos II.
Abstract: En el último seminario vimos un resultado de Komlós, Sárközy y Szemerédi de 1995 sobre la existencia de árboles generadores de grado máximo acotado en grafos densos. Este resultado fue mejorado en 2001 por los mismos autores, quienes demostraron que se puede encontrar árboles generadores de grado máximo O(n/log n) en grafos densos. Recientemente, Kathapurkar y Montgomery presentaron una generalización de este resultado para grafos dirigidos. A diferencia de los resultados anteriores, la demostración de esta generalización no...
Multidimensional Apportionment Through Discrepancy Theory. & Determination of functions by the metric slope.
Speaker 1: Víctor Verdugo Title: Multidimensional Apportionment Through Discrepancy Theory. Abstract: Deciding how to allocate the seats of a house of representatives is one of the most fundamental problems in the political organization of societies, and has been widely studied over already two centuries. The idea of proportionality is at the core of most approaches to tackle this problem, and this notion is captured by the divisor methods, such as the Jefferson/D’Hondt method. In a seminal work, Balinski and Demange extended the...
Solidarity Cover Problem.
Abstract: This work started with a real-world problem where the task was to partition a set of locations into disjoint subsets such that each subset is spread in a way that it covers the whole set with a certain radius. This made us formalizing the following problem which we call Solidarty Cover Problem. Given a finite set S, a metric d, and a radius r, and a number of partitions m. We define a subset C of S to be an r-cover if B(C,r)=S. The Solidarity Cover Problem is the problem of determining whether there exist m disjoint r-covers. We...
A multiple time renewal equation for neural assemblies with elapsed time model.
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.
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.
Abstract: Ver pdf
Prophet Inequalities via the Expected Competitive Ratio.
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.
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.
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...
