报告时间：2021年7月18日（星期日）10:00

报告地点：翡翠湖校区科教楼B座1710室

报 告 人：张国华 教授

工作单位：复旦大学

举办单位：数学学院

报告简介：

Let a countable discrete group G act on a zero-dimensional compact metric space X. We say that the action admits comparison if for any clopen sets A and B, the condition, that for every G-invariant measure m on X we have the sharp inequality m(A)< m(B), implies that A is subequivalent to B, that is, there exists a finite clopen partition A1, ..., Ak for A, and elements g1, ..., gk in G such that g1(A1), ..., gk(Ak) are disjoint clopen subsets of B. We prove this property for actions of groups whose every finitely generated subgroup has subexponential growth. This is a joint work with Professor Tomasz Downarowicz.

报告人简介：

张国华，复旦大学教授、博士生导师。主要研究动力系统的复杂性理论和可数离散群作用动力系统的熵理论。在Mem. AMS, J. Reine Angew. Math., Adv. Math., JFA, JDE, ETDS等国际知名刊物上发表论文30余篇。2017年获国家自然科学基金优秀青年基金资助。