Activities This Week
AGNT
An Algebraic Approach to the Cotangent Complex (online meeting)
Mar 27, 12:10—13:10, 2023, -101
Speaker
Amnon Yekutieli (BGU)
Abstract
Let $B/A$ be a pair of commutative rings. We propose an algebraic approach to the cotangent complex $L_{B/A}$. Using commutative semi-free DG ring resolutions of B relative to A, we construct a complex of $B$-modules $LCot_{B/A}$. This construction works more generally for a pair $B/A$ of commutative DG rings.
In the talk we will explain all these concepts. Then we will discuss the important properties of the DG $B$-module $LCot_{B/A}$. It time permits, we’ll outline some of the proofs.
It is conjectured that for a pair of rings $B/A$, our $LCot_{B/A}$ coincides with the usual cotangent complex $L_{B/A}$, which is constructed by simplicial methods. We shall also relate $LCot_{B/A}$ to modern homotopical versions of the cotangent complex.
Slides: https://sites.google.com/view/amyekut-math/home/lectures/cotangent
Operator Algebras and Operator Theory
Description of Intermediate C*-Algebras for Noncommutative Crossed Products
Mar 29, 12:00—13:00, 2023, Minus 101
Speaker
Apurva Seth (BGU)
Abstract
This is a joint work with Prof. Ilan Hirshberg and Dr. Tattwamasi Amrutam. Let $\Gamma$ be a discrete group with the property-AP. We give conditions for the inclusion of unital separable C-algebras $A \subset B$ for which every intermediate C-algebra $C$, such that $A \rtimes \Gamma \subset C \subset B \rtimes \Gamma$ is a crossed product. We shall end this talk with some natural classes of inclusion satisfying the above mentioned conditions.
BGU Probability and Ergodic Theory (PET) seminar
Actions of random quotients on hyperbolic CAT(0) cube complexes
Mar 30, 11:10—12:00, 2023, -101
Speaker
Thomas Ng (Technion - Israel Institute of Technology)
Abstract
Combinatorial nonpositive curvature of CAT(0) cube complexes plays a surprising role both in topological characterization of hyperbolic 3-manifolds and also in studying algebraic properties of random groups.
With Einstein, Krishna MS, Montee, and Steenbock, we introduce a new model for random quotients of free products that generalizes Gromov’s destiny model. I will discuss challenges that arise in this new setting, connections to work of Futer-Wise and Martin-Steenbock on cubulating quotients, as well as applications to residual finiteness using recent work of Einstein and Groves on relative cubulation.
Operator Algebras and Operator Theory
TBA
Mar 30, 14:00—15:00, 2023, Minus 101
Speaker
TBA