Hrvoje Stojanovic, Vanderbilt University
https://vanderbilt.zoom.us/j/99140969389

 Nate Tenpas, Vanderbilt University

Bogdan Chornomaz (Vanderbilt)
Topology & Group Theory Seminar page for Zoom meeting information

S-machines were first introduced in a 1997 paper (published only in 2002) by Sapir, Birget, and Rips, where they were used to prove that a finitely generated group G with a word problem of complexity T(n) can be embedded into a finitely presented group H with Dehn function of G in H at most T(n)4. This bound hinges on the fact that S-machine can emulate a Turing machine in time T(n)3. We improve this emulation bound to T(n)1+ε for any ε>0, which, hopefully, implies that the bound on the Dehn function can be improved to T(n)2+ε.

Jiawei Han, Vanderbilt University

Mikael Rordam, University of Copenhagen
Zoom ID 94393956397 Subfactor Seminar page for Zoom meeting information

There are several naturally occurring interesting examples of inclusions of simple C*-algebras with the property that all intermediate C*-algebras likewise are simple. By an analogy to von Neumann algebras, we refer to such inclusions as being C*-irreducible. We give an intrinsic characterization of C*-irreducible inclusions, and use this characterization to exhibit (and revisit) such inclusions, both known ones and new ones, arising from groups and dynamical systems. By a theorem of Popa, an inclusion of II_1-factors is C*-irreducible if and only if it is irreducible with finite Jones index. We explain how one can construct C*-irreducible inclusions from inductive limits. In a recent joint work with Echterhoff we consider when inclusions of the form $A^H \subseteq A \rtimes G$ are C*-irreducible, where G and H are groups acting on a C*-algebra A. Such inclusions in the setting of II_1 factors were considered by Bisch and Haagerup.

Katrina Morgan, Northwestern University
PDE Seminar page for Zoom meeting information

Alex Cloninger, University of California – San Diego
Computational Analysis Seminar page for Zoom meeting information

Junyan Zhang, Johns Hopkins University
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Changying Ding, Vanderbilt University
Zoom ID 94393956397 Subfactor Seminar page for Zoom meeting information

Bernhard Bodmann, University of Houston
Computational Analysis Seminar page for Zoom meeting information

Federico Pasqualotto, Duke University
PDE Seminar

Federico Pasqualotto, Duke University
PDE Seminar page for Zoom meeting information

Corey Jones, North Carolina State University
Zoom ID 94393956397 Subfactor Seminar page for Zoom meeting information

Yvonne Ou, University of Delaware
Computational Analysis Seminar page for Zoom meeting information

Sorin Popa, UCLA
Subfactor Seminar page for Zoom meeting information Zoom ID 94393956397

Peter Hinow, University of Wisconsin, Milwaukee
Computational Analysis Seminar page for Zoom meeting information

Ákos Nagy, UC Santa Barbara
PDE Seminar page for Zoom meeting information

James Tener, ANU Mathematical Sciences Institute
Zoom ID 94393956397 Subfactor Seminar page for Zoom meeting information