Algebry operatorów i ich zastosowania w fizyce
2006/2007 | 2007/2008 | 2008/2009 | 2009/2010 | 2010/2011 | 2011/2012 | 2012/2013 | 2013/2014 | 2014/2015 | 2015/2016 | 2016/2017 | 2017/2018 | 2018/2019 | 2019/2020 | 2020/2021 | 2021/2022 | 2022/2023 | 2023/2024 | 2024/2025
2014-06-05 (Czwartek)
Adam Skalski (Instytut Matematyczny PAN)
Haagerup approximation property for von Neumann algebras - old and new
The Haagerup approximation property for a von Neumann algebra with a fixed faithful tracial state was introduced over 30 years ago by Marie Choda, who was motivated by the Haagerup property for discrete groups (which was then 4 years old). Recent study of the latter property in the world of quantum groups led naturally to the introduction of the Haagerup property for a von Neumann algebra with a fixed normal faithful semifinite weight. We will describe the latter, show that it does not depend on the choice of the weight and present some further equivalences. Based on joint work with Martijn Caspers (and also Rui Okayasu and Reiji Tomatsu).
2014-05-29 (Czwartek)
Biswarup Das (Instytut Matematyczny PAN)
Eberlein Compactiication of Locally Compact Quantum Group
I will discuss a generalisation of the notion of Eberlein compactification within the category of Universal Locally compact quantum group. I will also discuss a generalisation of the well-known classical decomposition theorem namely almost periodic functions form a complemented Banach space within the algebra of Eberlein compact functions, in the context of quantum groups. This is an attempt to study the notion of weakly periodic functions on quantum groups.(Joint work with Matthew Daws.)
2014-04-24 (Czwartek)
Paweł Kasprzak (KMMF)
On quantum groups with projection
In this talk I will discuss Hopf and C*-algebraic aspects of the theory of quantum groups with projection. On the Hopf level I will describe the Hopf algebra decomposition into the image of the projection and the sub-algebra of invariants, the former being a Hopf algebra whereas the later is a Hopf algebra in the braided sense. On the C*-level I will discuss the multiplicative unitary decomposition assigned to a projection.
2014-04-10 (Czwartek)
Biswarup Das (IM PAN)
Godemont decomposition theorem for quantum groups
Godemont decomposition theorem for a locally compact classical group G states that a weakly almost periodic function on G can be uniquely decomposed into an almost periodic part, and a singular part (singular in the sense that it lies in the kernel of the invariant mean on the set of weakly almost periodic functions on G). We will discuss how far this theorem can be generalised to locally compact quantum groups.
2014-04-03 (Czwartek)
Biswarup Das
Godemont decomposition theorem for quantum groups
Godemont decomposition theorem for a locally compact classical group G states that a weakly almost periodic function on G can be uniquely decomposed into an almost periodic part, and a singular part (singular in the sense that it lies in the kernel of the invariant mean on the set of weakly almost periodic functions on G). We will discuss how far this theorem can be generalised to locally compact quantum groups.
2014-03-27 (Czwartek)
Paweł Kasprzak (KMMF)
Rieffel deformation of tensor functor and braided quantum groups (II)
In this talk we apply Rieffel deformation to the tensor product considered as a functor in the category of C* -algebras with an abelian group action. In the case of the Rieffel deformation applied to a quantum group with the abelian group acting by automorphisms the deformed tensor product enables us to view the deformed object as a braided quantum group. Weuse this construction as a hint towards a general theory of braided quantum groups. In particular we construct a bicharacter together with the dual braided quantum group. We employ our methode to get a braided quantum Minkowski space. Its description in terms of the deformedspace-time coordinates is provided.
2014-03-13 (Czwartek)
Paweł Kasprzak (KMMF)
Rieffel deformation of tensor functor and braided quantum groups
In this talk we apply Rie ffel deformation to the tensor product considered as a functor in the category of C* -algebras with an abelian group action. In the case of the Rieffel deformation applied to a quantum group with the abelian group acting by automorphisms the deformed tensor product enables to view the deformed object as a braided quantum group. Weuse this construction as a hint towards a general theory of braided quantum groups. In particular we construct a bicharacter together with the dual braided quantum group. We employ our methode to get a braided quantum Minkowski space. Its description in terms of the deformed space-time coordinates is provided.
2014-03-06 (Czwartek)
Martijn Caspers (Muenster University)
Schur and Fourier multipliers of an amenable group acting on non-commutative L^p-spaces
Fourier and Schur multipliers of groups are indispensible in the study of approximation properties and various problems involving non-commutative harmonic analysis. In this talk we introduce L^p-Fourier multipliers for arbitrary groups and study the close relation between such a multiplier and its corresponding Schur multiplier. In particular, we show how to generalize a result by Neuwirth and Ricard stating that for a discrete amenable group, the completely bounded norm of a L^p-Fourier multiplier equals the completely bounded norm of its associated Schur multiplier. We will relate our results to approximation properties of groups and non-commutative L^p-spaces. This is joint work with Mikael de la Salle.
2014-02-27 (Czwartek)
Piotr M.Sołtan (KMMF)
I will recall the notion of amenability of a locally compact quantum group and prove a theorem providing a characterization of this property in terms of injectivity of the von Neumann algebra associated to the dual (quantum) group.
O średniowalności i injektywności lokalnie zwartych grup kwantowych
On amenability and injectivity of locally compact quantum groups
Przypomnę pojęcie średniowalności lokalnie zwartej grupy kwantowej i udowodnię twierdzenie charakteryzujące tę własność w terminach injektywności algebry von Neumanna związanej z (kwantową) grupą dwoistą.
I will recall the notion of amenability of a locally compact quantum group and prove a theorem providing a characterization of this property in terms of injectivity of the von Neumann algebra associated to the dual (quantum) group.
2014-02-20 (Czwartek)
Hun Hee Lee (Department of Mathematical Sciences, Seoul National University)
Weighted Fourier algebras and their spectrum
In this talk we will discuss a model for a weighted version of Fourier algebras on locally compact groups. Note that the Fourier algebra is the L1-algebra of a co-commutative (l.c.) quantum group. We first introduce the concept of "weight" in this context and some examples of "weights". By introducing a "weight" we finally get a new commutative Banach algebra. If we recall that the spectrum of the Fourier algebra is nothing but the underlying group itself (as a topological space), then it is natural to be interested in determining the spectrum of weighted algebras. We will demonstrate that the spectrum of the resulting commutative Banach algebra is realized inside the complexification of the underlying Lie group by focusing on the case of E(2) and determine them in some concrete cases. There will be a short discussion for the possible quantum extension of this theory in the end of the talk.
2014-01-23 (Czwartek)
Mateusz Wasilewski (Wydział MIMUW)
O formach dwuliniowych na C*-algebrach
On bilinear forms on C*-algebras
2014-01-16 (Czwartek)
Przemysław Wojtaszczyk (Wydział MIMUW)
Przestrzeń Hilberta w teorii przestrzeni Banacha
Hilbert space in the theory of Banach spaces
2014-01-09 (Czwartek)
Paweł Kasprzak (KMMF)
Nierówność Grothendiecka (III)
On Grothendieck's inequality (III)
Zostanie pokazana równoważność przedstawionych wcześniej sformułowań nierówności Grothendiecka oraz jej związek z nierównością Bella oraz teorią grafów.
2013-12-12 (Czwartek)
Paweł Kasprzak (KMMF)
Nierówność Grothendiecka (III)
On Grothendieck's inequality (III)
Zostanie pokazana równoważność przedstawionych wcześniej sformułowań nierówności Grothendiecka oraz jej związek z nierównością Bella oraz teorią grafów.
2013-12-05 (Czwartek)
Paweł Kasprzak (KMMF)
Nierówność Grothendiecka (II)
On Grothendieck's inequality (II)
2013-11-28 (Czwartek)
Paweł Kasprzak (KMMF)
O nierówności Grothendiecka
On Grothendieck's inequality
2013-11-21 (Czwartek)
Jyotishman Bhowmick (Universitetet i Oslo, Norway)
Examples of compact quantum metric spaces coming from length functions
2013-11-14 (Czwartek)
Przemysław Majewski (KMMF)
Konforemne reprezentacje SO(6), cz.II
On conformal representations of the SO(6) group (II)
2013-11-07 (Czwartek)
Piotr Sułkowski (IFT UW)
Matrix models, invariants of algebraic curves, and chord diagrams
2013-10-31 (Czwartek)
Przemysław Majewski (KMMF)
Konforemne reprezentacje SO(6)
On conformal representations of the SO(6) group
2013-10-17 (Czwartek)
Stanisław L.Woronowicz (KMMF)
Konstrukcja GNS dla miary Haara na lokalnie zwartej grupie kwantowej. Uogólnionione wektory cykliczne a operator Kaca Takesakiego. Dyskusja wzorów wyrażających całki po miarach Haara przez ważone ślady
On the GNS constraction for the Haar measure on locally compact quantum group. Generalized cyclic vectors and Kac-Takesaki operator. Remarks on formulae describing Haar integrals by weighted traces
2013-10-10 (Czwartek)
Wojciech Matysiak (WMiNI PW)
O wynikach Biane'a na temat kwantowego procesu Bessela
On Biane's approach to the quantum Bessel process
Niech H oznacza grupę Heisenberga. Rozważać będziemy pewną półgrupę całkowicie dodatnich odwzorowań C*-algebry grupowej H, którą interpretuje się (poprzez konstrukcję odpowiedniej dylatacji na przestrzeni Focka) jako półgrupę niekomutatywnego ruchu Browna. Następnie pokażemy, w jaki sposób obcięcie tej podgrupy do (komutatywnej) podalgebry funkcji radialnych na grupie Heisenberga, zwane półgrupą kwantowego procesu Bessela, interpretuje się jako klasyczny proces Markowa na spektrum C*-podalgebry funkcji radialnych na H (zbiór ten nazywany jest wiatrakiem Heisenberga). Zasygnalizujemy także związek tego klasycznego procesu z jednym z kwadratowych harnessów skonstruowanych przez W.Bryca i J.Wesołowskiego, tzw. procesem bi-1-Poissona. Referowane wyniki pochodzą z kilku prac Philippe Biane z lat 1996--2010.