# Taipei Postdoc Seminar

## April 21 (Wed.) 14:00-15:00 Yan-Yu Chen (National Taiwan University) Venue: Lecture Hall 5F, Cosmology Building, NTU Title: Global Dynamics on One-dimensional Excitable Media

Abstract:
The FitzHugh–Nagumo system has been studied extensively for several decades. It has been shown numerically that pulses are generated to propagate and then some of the pulses are annihilated after collision. For the mathematical understanding of these complicated dynamics, we investigate the global dynamics of a one-dimensional free boundary problem in the singular limit of a FitzHugh–Nagumo type reaction–diffusion system. By introducing the notion of symbolic dynamics, we show that the asymptotic behaviors of solutions are classified into three categories: (i) the solution converges uniformly to the resting state; (ii) the solution converges to a series of traveling pulses propagating in either the same direction or both directions; and (iii) the solution converges to a propagating wave consisting of multiple traveling pulses and two traveling fronts propagating in both directions.

This is a joint work with Professor Hirokazu Ninomiya and Professor Chang-Hong Wu.

2016

## Jan. 13, You Hung Hsu (NCTS) Exceptional Collections, t-structures and Categorical Action Mar. 10, Shih-Yu Chen (AS) On Deligne's Conjecture for Symmetric Fourth L-functions of Hilbert Modular Forms Mar. 24, Wei-Guo Foo (AS) Some Remarks on Second Order Ordinary Differential Equations Apr. 7, Jun-Wen Peng (University of Rochester) An Embedding of the Arboreal Galois Group for PCF Map

### The Taipei Postdoc Seminar is a weekly seminar that is organized jointly by the Institute of Mathematics of Academia Sinica and the National Center for Theoretical Sciences during the regular academic year. The seminar is held in these two mathematical institutions, with each one of them hosting the event approximately once every two weeks. The National Taiwan University, Academia Sinica, and the NCTS, together employ a significant number of postdoctoral fellows in mathematics from all over the world every year. The diverse scientific and cultural backgrounds of these postdocs create a unique environment of learning, and the goal of the Taipei Postdoc Seminar is to take advantage of this opportunity by bringing together all these postdocs once in a week in an informal-style seminar to enhance discussions and exchange of ideas among the participants. It is our belief that not only will this seminar encourage and eventually lead to more collaboration among mathematicians in Taipei, but it will also give the participants a chance to broaden their own scientific viewpoints. It is our hope that this seminar will greatly enrich the academic experience of the postdoctoral fellows during their stay in Taipei. Organizers: Wei-Bo Su (wbsu@gate.sinica.edu.tw), Peng-Jie Wong (pengjie.wong@ncts.tw)

Former organisers