Monday Analysis Seminar: On Popa’s Embedding Problem

2012-1-16 14:45 - 2012-1-16 16:15
Faculty of Science Buliding #3 Room 210
Yasumichi Matsuzawa (Hokkaido Univ)
In 2005, Sorin Popa initiated to study a Polish group which is isomorphic to a closed subgroup of the unitary group of a II_1-factor. Such a group is called finite type. Popa introduced this class of groups to state his cocycle superrigidity theorem. A typical property of finite type groups is to have a compatible bi-invariant metric. The question which we discuss in the talk is whether the converse is true. We start with definitions of basic notions and discuss about this question.