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Texas A&M University

Events for 02/21/2024 from all calendars

Numerical Analysis Seminar

iCal  iCal

Time: 3:00PM - 4:00PM

Location: BLOC 302

Speaker: Harbir Antil, George Mason University

Title: TBA

Abstract: TBA

Groups and Dynamics Seminar

iCal  iCal

Time: 3:00PM - 4:00PM

Location: BLOC 123

Speaker: Alain Valette, University of Neuchâtel

Title: Maximal Haagerup subgroups in Zn x SL2(Z)

Abstract: The Haagerup property is a strong negation of Kazhdan's property (T). In a countable group, every Haagerup subgroup is contained in a maximal one. We propose to classify maximal Haagerup subgroups in the semi-direct product Gn=Zn x SL2(Z), where the action of SL2(Z) on Zn is induced by the unique irreducible representation of SL2(R) on Rn (with n>1). We prove that there is a dichotomy for maximal Haagerup subgroups in Gn: either (amenable case) they are of the form Zn x K, with K maximal amenable in SL2(Z); or (non-amenable case) they are transverse to Zn. This extends work by Jiang and Skalski for n=2. In joint work with P. Jolissaint, for n even, we prove the stronger result that the von Neumann algebra of Zn x K (K as above) is maximal Haagerup in the von Neumann algebra of Gn. This involves looking at the orbit equivalence relation induced by SL2(Z) on the n-torus, and proving that it satisfies a dichotomy: every ergodic sub-equivalence relation is either rigid or hyperfinite. This extends a result by Ioana for n=2.

Student/Postdoc Working Geometry Seminar

iCal  iCal

Time: 9:00PM - 10:10PM

Location: BLOC 628

Speaker: Derek Wu, TAMU

Title: Boij-Soederberg II