Asymptotic expansion for
groupoids and Roe type algebras
报告专家：章嘉雯 副教授 （复旦大学）
报告时间：11月28日（周五）10:00-11:00
报告地点：四川大学数学学院西202
报告摘要：
In this talk, we introduce a notion of expansion for groupoids, which recovers the classical notion of expander graphs by a family of pair groupoids and expanding actions in measure by transformation groupoids. We also consider an asymptotic version for expansion and establish structural theorems, showing that asymptotic expansion can be approximated by domains of expansions. On the other hand, we introduce dynamical propagation and quasi-locality for operators on groupoids and the associated Roe type algebras. Our main results characterize when these algebras possess block-rank-one projections by means of asymptotic expansion, which generalises the crucial ingredients in previous works to provide counterexamples to the coarse Baum-Connes conjecture. This is a joint work with Xulong Lu and Qin Wang.
专家简介：
章嘉雯，复旦大学数学科学学院副教授，博导，主要从事泛函分析的教学和科研工作，尤其在高指标理论中核心猜想粗Baum-Connes猜想、指标代数的结构等研究上取得了突出成果。在 Adv. Math.，CMP，IMRN，Trans. AMS.，JFA等权威期刊发表论文20多篇。获得2024国家自然科学基金优秀青年科学基金、上海市领军人才（海外）称号、参与国家重点研发计划青年科学家项目。
邀请人：余佳洋
