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.
Variational principles and equilibrium states for (semi)group actions.
ABSTRACT: The search for a thermodynamic formalism for dynamical systems aims to prove the existence of invariant probability measures which maximize the topological pressure, besides reporting on their statistical properties. A special feature of the classical thermodynamic formalism for Ruelle expanding maps, which becomes an important tool in many applications including applications to multifractal analysis or large deviations, is the upper-semicontinuity of the Kolmogorov-Sinai entropy map. Simple examples illustrate that this property...
Strategic and Structural Aspects of Bitcoin Mining.
Abstract: Just over a decade ago, Satoshi Nakamoto published a landmark white paper outlining the backbone protocol to Bitcoin, arguably the world’s first mainstream digital currency. Through the Nakamoto protocol and blockchain technology, users can reliably agree upon a common transaction history maintained by miners on the public Bitcoin ledger in a decentralised and anonymous fashion. This is possible in part because agents within the protocol are assumed to be strategic rather than adversarial—a fair assumption when creating...
Simulating Microenvironmental effects in tumor progression.
Abstract. In this presentation, we will see the preliminary numerical exploration of a mathematical approach that captures and explores a wide range of mechanisms and biological variabilities in tumor progression is presented. Precisely, the mathematical model captures cell-cell interactions including micro-environment effects in solid tumor progression. The biological principle consists in to assume that the tumor cells interact with Tumor-Associated Macrophages, and simultaneously with the extracellular matrix. Such two different mechanisms...
Embedding de árboles en grafos expansores.
Resumen: Vamos hablar sobre el paper “Tree Embeddings”, de Penny E. Haxell. En este paper, Penny muestra un teorema general para embedding de árboles en grafos expansores, y como aplicación se probará un caso particular de la conjetura de Erdős-Sós, que pregunta si un grafo G con grado promedio a lo menos t-1 contiene todo árbol T con t aristas como subgrafo. Ella muestra que la conjetura es verdad si el grafo G no contiene K_{2,r}.
Unraveling parking on random trees via random graphs.
Abstract: Imagine a plane tree together with a configuration of particles (cars) at each vertex.Each car tries to park on its node, and if the latter is occupied, it moves downward towards the root trying to find an empty slot.When the underlying plane tree is a critical Galton–Watson conditioned to be large, and when the cars arrivals are i.i.d. on each vertex, we observe a phase transition:- when the density of cars is small enough, all but a few manage to park safely,- whereas when the density of cars is high enough, a positive...
A regularity criterion for a 3D chemo-repulsion system and its application to a bilinear optimal control problem.
Abstract: We will study a bilinear optimal control problem associated to a 3D chemo-repulsion model with linear production. We prove the existence of weak solutions, and establish a regularity criterion to get global-in-time strong solutions. As a consequence, we deduce the existence of a global optimal solution with bilinear control, and, using a Lagrange multipliers theorem in Banach spaces, we derive first-order necessary optimality conditions for each local optimal solution.
Competencia escolar IMMC-Chile 2021: ¿Qué es el modelamiento matemático y cómo participar?
Webinar sobre modelamiento matemático y el proceso de selección de Chile para Competencia Internacional de Modelamiento Matemático IMMC – Chile 2021, cuyas inscripciones ya están abiertas. Esta actividad está organizada por el Laboratorio de Educación del Centro de Modelamiento Matemático CMM-Edu y se realizará el jueves 8 de octubre 2020 a las 18:00 horas en modalidad online, vía Zoom. Les sugerimos inscribirse para recibir el link de Zoom el día del evento. Se hará asimismo simultáneamente transmisión vía YouTube. Les agradecemos...
Números de Ramsey para árboles: Caso Doble estrella S(2m,m).
Abstract: Dados dos enteros n y m, denotamos por S(n,m) al grafo que consiste en dos estrellas de tamaño n y m, respectivamente, que están unidas por sus centros mediante una arista. En esta charla se pretende entregar el contexto histórico que tiene la teoría de Ramsey para árboles y además se mostrará una nueva cota superior para S(2m,m), lo que responde parcialmente una pregunta de Norin et.al del 2016. Se explicará a grandes rasgos la demostración de esta cota y además la estructura que tiene el coloreo extremal.
Principal-Agent problem in insurance: from discrete-to continuous-time.
Abstract: In this talk we present a contracting problem between an insurance buyer and the seller, subject to prevention efforts in the form of self-insurance and self-protection. We start with a static formulation, corresponding to an optimization problem with variational inequality constraint, and extend the main properties of the optimal contract to the continuous-time formulation, corresponding to a stochastic control problem in weak form under non-singular measures.
Acerca de la derivada de una conjugación entre dos transformaciones de tipo Gauss.
ABSTRACT: A principios del siglo XX, H. Minkowski definió una función (“Question-Mark function”, Q) que establece una correspondencia uno a uno entre racionales y soluciones reales en [0,1] de polinomios cuadráticos con coeficientes enteros. Desde un punto de vista dinámico, Q es una conjugación topológica entre la transformación de Farey y el Tent-map. Entre sus propiedades se encuentra también que Q es una función singular, es decir, Lebesgue-c.t.p su derivada existe y es igual a cero (Salem,1943). En trabajos más recientes,...
