Functional Analysis Seminar UMD College Park
Functional Analysis Seminar UMD College Park
Organized by Christian Rosendal and Srivatsav Kunnawalkam Elayavalli
The seminar will be in the Colloquium room in Kirwan Hall, Mondays 1PM to 2PM. We will have lunch with the speaker usually before the seminar in Yahentamitsi.
September 8th, 2025: Srivatsav Kunnawalkam Elayavalli (UMD).
Title: Kickoff, Mixed identity freeness, and applications.
Abstract: I will begin the functional analysis seminar series with the first talk. First will be an organizational component wherein I will explain the details of the seminar, describe up a rough plan of the semester's invited speakers and their research directions. Then I will demonstrate the notion of mixed identity freeness in certain categories, and explain applications to problems in C*-algebras, and continuous model theory.
September 15th, 2025: Aareyaan Manzoor (University of Waterloo).
Title: There is a non-Connes embeddable equivalence relation.
Abstract: Connes embeddability of a group is a finite dimensional approximation property. Turns out this property depends only on the so-called group von Neumann algebra. The property can be extended to all von Neumann algebras. The fact that there is a von Neumann algebra without this property was proved in 2020 using a quantum complexity result MIP*=RE. It is still open for groups. I will discuss the best-known partial result, which is that there is a group action without this property. In particular, this implies the negation to the Aldous-Lyons conjecture, a big problem in probability theory.
September 29th, 2025: Koichi Oyakawa (McGill University).
Title: Hyperfiniteness of the boundary action of virtually special groups
Abstract: A Borel equivalence relation on a Polish space is called hyperfinite if it can be approximated by equivalence relations with finite classes. This notion has long been studied in descriptive set theory to measure complexity of Borel equivalence relations. Recently, a lot of research has been done on hyperfiniteness of the orbit equivalence relation on the Gromov boundary induced by various group actions on hyperbolic spaces. In this talk, I will explain my attempt to explore this connection of Borel complexity and geometric group theory for another intensively studied geometric object, which is CAT(0) cube complexes. More precisely, we prove that for any countable group acting virtually specially on a CAT(0) cube complex, the orbit equivalence relation induced by its action on the Roller boundary is hyperfinite.
October 27th, 2025: Bin Sun (Michigan State University).
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November 17th, 2025: Jason Behrstock (CUNY).
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December 1st, 2025: Kevin Beanland (Washington and Lee University).
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