Link do kanału youtube: https://www.youtube.com/channel/UCnHfrrAKk9Jaaw8oC2s_dSQ

Zoom platform link: https://us02web.zoom.us/j/83662713532?pwd=MFpVS1NlQkt4THVtMGdYNTR2Ym93UT09

Meeting ID: 836 6271 3532 Passcode: 764579

- Paul F. Baum
- Francesco D'Andrea
- Ludwik Dąbrowski
- Søren Eilers
- Piotr M. Hajac
- Frédéric Latrémolière
- Ryszard Nest
- Marc A. Rieffel
- Andrzej Sitarz
- Wojciech Szymański
- Adam Wegert

2023-03-08, 17:15, 405 IMPAN & ZOOM

MAYUKO YAMASHITA (RIMS, Kyoto University, Japan)

**TOPOLOGICAL MODULAR FORMS AND VANISHING OF HETEROTIC ANOMALY**In this talk, based on my work with Yuji Tachikawa, I will explain how to use algebraic topology to solve the physical problem of vanishing anomalies in heterotic string theories. We translate this physical problem into the mathematical problem of showing that a certain transformation of generalized...

2023-03-01, 17:15, 405 IMPAN & ZOOM

ARUP KUMAR PAL (Indian Statistical Institute, Delhi Centre, India)

**CRYSTALLIZATION OF THE C*-ALGEBRA C(SUq(n+1))**We will explain how to obtain the crystal limit of the C*-algebra of continuous functions on the quantum SU(n+1) group as a C*-algebra given by generators and relations. These relations are derived by looking at the irreducible representations of the C*-algebras C(SUq(n+1)) for q>0 and, after ...

2023-02-22, 17:15, 405 IMPAN & ZOOM

TOMASZ MASZCZYK (University of Warsaw, Poland)

**HOCHSCHILD COHOMOLOGY FOR ABSTRACT CONVEXITY AND SHANNON ENTROPY**The Shannon entropy was introduced as a statistical measure of information loss but appeared in other fields of mathematics as well. We plan to sketch its relations with polylogarithms and motives after Cathelineau, Dupont, Bloch, Goncharov, Elbaz-Vincent, and Gangl, a cohomological interpretation b...

2023-01-25, 17:15, 405 IMPAN & ZOOM

Piotr M. Hajac (IMPAN)

**THE COVARIANT FUNCTORIALITY OF GRAPH ALGEBRAS**In the standard category of directed graphs, morphisms respect the lengths of paths. However, this requirement is way too strong to present natural *-homomorphisms between graph C*-algebras as covariantly induced from morphisms of graphs, so we define a new category of directed graphs where morphism...

2023-01-18, 17:15, 405 IMPAN & ZOOM

HUA WANG (IMPAN)

**CONSTRUCTIONS OF QUANTUM GROUPS WITH THE RAPID DECAY PROPERTY**Starting with Haagerup's seminal work, the rapid decay (RD) property was systematically studied by Jolissaint for discrete groups, and later by Vergnioux, in the setting of discrete quantum groups. Through the work of many hands, the RD property is nowadays an interesting approximation p...

2023-01-11, 17:15, 405 IMPAN & ZOOM

AHMAD REZA HAJ SAEEDI SADEGH (Northeastern University)

**DEFORMATION SPACES, GETZLER'S RESCALING, AND AN EQUIVARIANT INDEX THEOREM FOR LIE GROUPOIDS**In recent work, Higson and Yi developed a new perspective on Getzler's symbol calculus, reinterpreting the latter in terms of a convolution algebra of sections of the rescaled bundle over the tangent groupoid of a spin manifold. We generalize the construction of the rescaled bundle to ...

2022-12-21, 17:15, 405 IMPAN & ZOOM

MARIUSZ TOBOLSKI (Uniwersytet Wrocławski)

**THE CONTRAVARIANT FUNCTORIALITY OF GRAPH ALGEBRAS**We introduce a subcategory of directed graphs for which the construction of Leavitt path algebras induces a contravariant functor into the category of algebras. Then we prove a theorem stating under which conditions this functor turns pushouts of directed graphs into pullbacks of algebras. Finally, ...

2022-12-14, 17:15, 405 IMPAN & ZOOM

JACEK KRAJCZOK (University of Glasgow)

**APPROXIMATION PROPERTIES FOR LOCALLY COMPACT QUANTUM GROUPS**One of the most widely studied properties of groups is the notion of amenability. In one of its many formulations, it gives us a way of approximating constant functions by functions in the Fourier algebra. The notion of amenability was relaxed in various directions. For instance, a very weak form of...

2022-12-07, 17:15, 405 IMPAN & ZOOM

JACK SPIELBERG (Arizona State University)

**RELATIVE GRAPHS AND PULLBACKS OF RELATIVE TOEPLITZ GRAPH ALGEBRAS**We generalize a result from a recent paper of Hajac, Reznikoff and Tobolski. In that paper they give conditions they call "admissibility" on a pushout diagram in the category of directed graphs implying that the C*-algebras of the graphs form a pullback diagram. We consider a larger catego...

2022-11-30, 17:15, 405 IMPAN & ZOOM

MATTHIAS SCHÖTZ (IMPAN)

**GELFAND-NAIMARK THEOREMS OF ORDERED *-ALGEBRAS**Ordered *-algebras (i.e. unital *-algebras endowed with a quadratic module of "positive&...