活动时间：2022-09-29 16:00

活动地点：腾讯会议 970-819-793

主讲人：M. Reissig

主讲人中文简介：

德国佛莱贝格科技大学（TU Bergakademie Freiberg, Germany），教授，博士生导师，主要研究偏微分方程解的适定性及应用分析。中德“偏微分方程分析及应用”国际合作项目德方重要成员，先后组织21个国际数学学术会议及分组会议，50余次受邀在国际数学学术会议上作学术报告，任若干个国际数学期刊的编委，在包括数学四大顶级期刊《Math. Anal.》在内的国际重要核心期刊上发表高水平论文100余篇，主持德国国家、州政府基金20余项，出版学术专著5部，培养了10余名优秀的博士生，在英国、德国、法国等的大学里任副教授、教授。

活动内容摘要：

In this lecture we continue our discussion of global (in time) existence of Sobolev solutions. We show how to decrease the lower bound of admissible exponents in the power nonlinearities by waiving the uniqueness of solutions. The main goal is to apply a Schauder's fixed point argument instead of Banach's fixed point theorem. It turns out that this is possible for wave models with integrable (in time) speed of propagation. This allow to prove existence of solutions with uniformly with respect to all times compact support. Then some kind of regularity improvement (first data is supposed to vanish identically) allows to close the circle. The question for critical exponent has no meaning after this lecture.

主持人：秦玉明