• Tingueu el micròfon apagat tota l'estona excepte durant el "Cafè i galetes".
• Podeu tenir la càmera encesa si voleu, però en cas de saturaciò de línies, caldrà que la tanqueu.
• Si voleu fer una pregunta, si us plau demaneu torn a través del xat i espereu que els moderadors us donin la paraula.
• Si és possible, entreu amb antelació. Els que no useu un compte de correu de la UPC haureu d'esperar a ser admesos per accedir-hi. (Això aplica a les sessions Google Meet de la UPC).

Dia: Dimecres, 1 de juny de 2022

Lloc: Aula T2 (2n pis), Facultat de Matemàtiques i Informàtica, UB.

També ONLINE https://ub-edu.zoom.us/j/99447996818?pwd=dHRLOHhvKzRxa1BZSThOVXdLaExVUT09

Zoom session Id: 994 4799 6818, pass: 458091

• Hora: 16h00m

A càrrec de: Evelyn Sander, George Mason University

Títol: Rotation vectors for torus maps using the weighted Birkhoff average

Resum: In this talk, I will discuss numerical methods for studying one- and two-dimensional invariant tori based on the weighted Birkhoff average. These methods do not rely on symmetries, such as time-reversal symmetry, nor on approximating tori by periodic orbits. These methods are combined with computational number theoretic methods for calculating whether a number (resp. vector) is rational (resp. nonresonant) up to a certain tolerance. Together, these methods make it possible to distinguish between chaotic regions, islands, and invariant tori, while simultaneously giving a highly accurate estimate of the frequency vector of each torus. We demonstrate these methods for Arnold’s circle map, Chirikov’s standard map and some of its variants, and to the three-dimensional standard volume-preserving map.

This work is in collaboration with James Meiss.

Last updated: Tue May 31 11:47:18 2022