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.

 

Investigating students’ coordinate systems

Event Date: Aug 03, 2021 in Education, Seminars

Abstract Starting around fifth grade, students are expected to represent and reason about various mathematical concepts (e.g., geometrical shapes, equations, and functions, etc.) using the Cartesian plane. However, the Cartesian plane is often taken for granted and students are assumed to develop proficiency in using the Cartesian plane in relatively unproblematic ways. My research has focused on understanding how students construct and make sense of coordinate systems, the foundational structure underlying graphs. I will (a) present a...

Some ideas to obtain energy in Chile.

Event Date: Jul 29, 2021 in Differential Equations, Seminars

Abstract:  In this talk we will present advances of a program that studies the modeling, analysis and control of models that describe the dynamics of wave energy converters (WEC) devices. In particular we will study two nonlinear models of an oscillating water column, where the one-dimensional shallow water equations in the presence of this device are essentially reformulated as two transmission problems: the first one is associated with a step in front of the device and the second one is related to the interaction between waves and a fixed...

Persistence and unique continuation principles in weighted spaces for solutions of the fractional Korteweg- de Vries equation.

Event Date: Jul 08, 2021 in Differential Equations, Seminars

Abstract: Persistence problems in weighted spaces have been studied for differ- ent dispersive models involving non-local operators. Generally, these equations do not propagate polynomial weights of arbitrary magni- tude, and the maximum decay rate is associated with the dispersive part of the equation. Altogether, this analysis is complemented by unique continuation principles that determine optimal spatial decay. This talk aims to show our results on the preceding questions for a weakly dispersive perturbation of the inviscid Burgers...

Generalized Malleable Scheduling via Discrete Concavity.

Event Date: Jul 07, 2021 in ACGO, Seminars

Abstract: In malleable scheduling, jobs can be executed simultaneously on multiple machines with the processing time depending on the number of allocated machines. Each job is required to be executed non-preemptively and in unison, i.e., it has to occupy the same time interval on all its allocated machines. In this talk, we discuss a generalization of malleable scheduling, in which a function f(S, j) determines the processing time of job j on machine subset S. Under different discrete concavity assumptions on 1/f(S,j), we show that the...

Concepciones sobre la evaluación de los formadores de Pedagogía en Matemática

Event Date: Jul 06, 2021 in Education, Seminars

Resumen Hoy en día, los docentes en matemática debiesen ser capaces de desarrollar diversas habilidades, especialmente en la resolución de problemas en los estudiantes, así como también monitorear su avance. Si bien la formación inicial docente debiese contribuir en el aprendizaje de estas capacidades en los futuros docentes, se observa que los egresados obtienen un 60.4% de respuestas correctas en el estándar de evaluación en la evaluación diagnóstica de la formación docente inicial ENED-FID, con una alta variación institucional....

Umbral del semigrado para ciclos Hamiltonianos antidirigidos.

Event Date: Jul 05, 2021 in Seminario de Grafos, Seminars

  Resumen: DeBiasio y Molla prueban que para dígrafos suficientemente grandes en n vértices con semigrado al menos n/2 + 1 se tiene un ciclo Hamiltoniano antidirigido. Más aún, es suficiente con semigrado n/2, a menos que el dígrafo sea uno de dos contraejemplos. En este seminario se hablará de la demostración del resultado, mostrando con más detalle el caso no-extremal que usa método de absorción.

Gravitational instantons in AdS: (anti-)self duality, topological terms, and conformal invariance.

Event Date: Jul 01, 2021 in Differential Equations, Seminars

Abstract: In this talk, we present some recent developments in obtaining conserved charges and thermodynamics of Euclidean, regular, and stationary solutions in general relativity. The introduction of topological terms renders the Euclidean Einstein-Hilbert on-shell action and Noether-Wald charges finite. The former is proportional to the Chern-Pontryagin index when evaluated at (anti-)self-dual solutions and the resemblance with instantons in Yang-Mills theory is evident. We work out the case of Taub-NUT/Bolt-AdS explicitly and compute the...

On the general problem of Erdos and Nesetril and its offsprings.

Event Date: Jun 30, 2021 in ACGO, Seminars

Abstract: In 1988, Erdos wrote about a problem he proposed with Nesetril: “One could perhaps try to determine the smallest integer h_t(D) for which every graph, with size h_t(D) edges and maximum degree at most D, contains two edges so that the shortest path joining these edges has length at least t. This problem seems to be interesting only if there is a nice expression for h_t(D).” This problem can be considered as the edge version of the famous (and hard) degree-diameter problem. It was the inspiration for a series of research...

Auctions with Intermediaries.

Event Date: Jun 23, 2021 in ACGO, Seminars

Abstract: In many markets, buyers do not bid directly in the auction, but instead, they are represented by intermediaries. This includes ad auctions, where some of the buyers might be represented by intermediaries like Ad agencies, Aggregators (e.g. Home Advisor), or Ad networks participating in an Ad Exchange. The presence of intermediaries creates the potential for collusion across buyers. Also, intermediaries have their own goals that depend on the contract between buyers and the intermediary, and will behave according to the incentives...