In this talk, I will report our recent research on a reaction-advection- diffusion competition model in a periodic habitat. We first investigate the global attractivity of a semi-trivial steady state (i.e., the competitive exclusion) for the periodic initial value problem. Then we establish the existence of the rightward spreading speed and its coincidence with the minimal wave speed for spatially periodic rightward traveling waves. Further, we obtain a set of sufficient conditions for the rightward spreading speed to be linearly determinate. Finally, we apply the obtained results to a prototypical reaction-diffusion model. This is a joint work with Dr. Xiaoqiang Zhao.

I will talk about the application of algebraic and number theoretical methods in the study of two combinatorial structures: difference sets in design theory and Cameron-Libler line class in finite geometry. The first concerns the multiplier conjecture, while the other has its origin in the study of permutation groups. What they have in common is that results from algebraic number theory plays important role in the proof. The second part is a joint work with Koji Momihara and Qing Xiang.

In this talk, I will establish a defect relation for holomorphic curves intersecting general divisors in projective varieties. Various consequences will be discussed.

学术报告题目: Preserver problems报告人: 李志光(Chi-Kwong Li)教授, 美国威廉玛丽学院摘要: Preserver problems concern the study of the characterizations of transformations on matrices or operators having some special properties such as leaving invariant certain functions, subsets, or relations. The study has motivations from theoretical and applied problems. We will give an introduction of the to...

学术报告报告人：刘跃教授(University of Texas at Arlington)题目： On the rotation- two- component- Camassa-Holm system modelling the equatorial water waves时间：2015年6月17日(星期三)下午10：00—11：00地点：数学系致远楼102欢迎各位参加

学术报告报告人：张平正教授(江苏大学)题目： The Holder continuity of the solution map to the Camassa - Holm equation in weak topology时间：2015年6月17日(星期三)上午10:30—11：30地点：数学系致远楼102欢迎各位参加

The reaction-diffusion systems, which have been frequently used as the models for many problems in physics, chemistry and biology, can give rise to an important solutions – the wave solutions. In this talk we begin with a brief introduction to the history and development of research done on the traveling waves solutions for reaction-diffusion systems, such as the shooting method, monotone iteration for monotone systems, perturbation approach, and application of Schauder’s fixed point theorem. We then present a recently developed method to study the existence of traveling wave fronts for a general class of models of predator-prey interaction described by reaction-diffusion systems. Our approach consists of a geometrical shooting argument and an analytic method by the construction of a Liapunov function and the use of Lasalle's invariance principle. Our approach can be extended to larger class of reaction-diffusion systems,

本报告以具体的例子来介绍数学中重整化方法的应用。考虑有理多面体中的整点个数问题，经典的结果由这多面体对应的簇的Riemman-Roch定理给出。我们现在重新考虑这一问题，以重整化方法给出了相应的答案。这不单给出了一个简单的方法，同时也说明了代数簇特征类的几何含义。