BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Arthur Jaffe (Harvard) DTSTART:20210608T150000Z DTEND:20210608T155000Z DTSTAMP:20260404T095208Z UID:Opalg21/1 DESCRIPTION:Title: Remembering the Future\nby Arthur Jaffe (Harvard) as part of Co nference on operator algebras and related topics in Istanbul\, 2021\n\nAbs tract: TBA\n LOCATION:https://stable.researchseminars.org/talk/Opalg21/1/ END:VEVENT BEGIN:VEVENT SUMMARY:Sorin Popa (UCLA) DTSTART:20210608T160000Z DTEND:20210608T165000Z DTSTAMP:20260404T095208Z UID:Opalg21/2 DESCRIPTION:Title: On the rigidity of virtual symmetries of II_1 factors\nby Sorin Popa (UCLA) as part of Conference on operator algebras and related topics in Istanbul\, 2021\n\n\nAbstract\nOne of the most fascinating aspects in the analysis of non-commutative spaces (aka von Neumann algebras)\, is the way their building data\, which is often geometric in nature\, impacts on their generalized (or virtual) symmetry picture. This is particularly the case for II_1 factors\, where virtual symmetries are encoded by subfactor s of finite Jones index\, a numerical invariant that can be quantized in i ntriguing ways. I will discuss some results and open problems that illustr ate the unique interplay between analysis and algebra/combinatorics entail ed by this interdependence\, that's specific to subfactor theory.\n LOCATION:https://stable.researchseminars.org/talk/Opalg21/2/ END:VEVENT BEGIN:VEVENT SUMMARY:Marcelo Laca (U Victoria) DTSTART:20210608T173000Z DTEND:20210608T181500Z DTSTAMP:20260404T095208Z UID:Opalg21/3 DESCRIPTION:Title: Toeplitz algebras of semigroups\nby Marcelo Laca (U Victoria) a s part of Conference on operator algebras and related topics in Istanbul\, 2021\n\n\nAbstract\nI will start by reviewing classical work of Coburn\, Douglas\, and Cuntz about C*-algebras generated by isometries\, and then p resent universal models for the Toeplitz algebras of submonoids of groups and for their boundary quotients\, discussing their uniqueness and simplic ity properties. This is recent joint work with Camila F. Sehnem that gener alizes previous results of Nica\, Li\, and Raeburn and myself.\n LOCATION:https://stable.researchseminars.org/talk/Opalg21/3/ END:VEVENT BEGIN:VEVENT SUMMARY:Hans Wenzl (UCSD) DTSTART:20210608T183000Z DTEND:20210608T191500Z DTSTAMP:20260404T095208Z UID:Opalg21/4 DESCRIPTION:Title: Subfactors\, Tensor Categories and Module Categories\nby Hans W enzl (UCSD) as part of Conference on operator algebras and related topics in Istanbul\, 2021\n\n\nAbstract\nWhen Vaughan Jones started to think abou t the notion of an index for subfactors\, the only known examples came fro m groups and their representations and from the embedding of groups H < G. In both cases the indices were integers. Vaughan's surprising examples wi th non-integer index were later connected to representations of the quantu m group U_q(sl2) and to representations of the loop group LSU(2). This was subsequently generalized to the construction of a sequence of subfactors for every representation of a semisimple Lie algebra.The question remains to construct subfactors corresponding to analogs of subgroups of Lie group s\; in modern language this amounts to classifying module categories of ce rtain tensor categories. Again\, Vaughan made important contributions for solving the problem for the sl_2 case constructing what is generally refer red to as Goodman-de la Harpe-Jones subfactors. While complete classificat ions are known for several Lie groupsof small rank\, the general problem i s still far from being solved. We give an overview of the current state of knowledge\, and present some explicit examples.\n LOCATION:https://stable.researchseminars.org/talk/Opalg21/4/ END:VEVENT BEGIN:VEVENT SUMMARY:Florin Radulescu (Univ. Roma) DTSTART:20210608T193000Z DTEND:20210608T201500Z DTSTAMP:20260404T095208Z UID:Opalg21/5 DESCRIPTION:Title: Common trends in Operator Algebra and Number Theory\nby Florin Radulescu (Univ. Roma) as part of Conference on operator algebras and rela ted topics in Istanbul\, 2021\n\n\nAbstract\nMany years ago (almost 30) Va ughan Jones initiated an approach to a new program of understanding of aut omorphic forms as Operator Algebra objects. There are naturally associated $II_1$ factors ( in the free groups factors series) His original motivati on was to understand if Hecke subgroups could be possibly related to a mor e natural construction of non-integer index subfactors in free group facto rs.. There is one "mystery trace vector (s)" which one would like to under stand\, and this showed up again in his late work. I will discuss these to pics and their relations to other problems in number theory that have a na tural Operator Algebra counterpart.\n LOCATION:https://stable.researchseminars.org/talk/Opalg21/5/ END:VEVENT BEGIN:VEVENT SUMMARY:Ivan Bardet (Univ. Lyon) DTSTART:20210609T130000Z DTEND:20210609T134500Z DTSTAMP:20260404T095208Z UID:Opalg21/6 DESCRIPTION:Title: Approximate tensorization of the relative entropy for noncommuting conditional expectations\nby Ivan Bardet (Univ. Lyon) as part of Confe rence on operator algebras and related topics in Istanbul\, 2021\n\n\nAbst ract\nI will present a new generalisation of the strong subadditivity of t he entropy to the setting of general conditional expectations onto arbitra ry finite-dimensional von Neumann algebras. The latter inequality\, which we call approximate tensorization of the relative entropy\, can be express ed as a lower bound for the sum of relative entropies between a given dens ity and its respective projections onto two intersecting von Neumann algeb ras in terms of the relative entropy between the same density and its proj ection onto an algebra in the intersection\, up to multiplicative and addi tive constants. In particular\, our inequality reduces to the so-called qu asi-factorization of the entropy for commuting algebras\, which is a key s tep in modern proofs of the logarithmic Sobolev inequality for classical l attice spin systems.\n LOCATION:https://stable.researchseminars.org/talk/Opalg21/6/ END:VEVENT BEGIN:VEVENT SUMMARY:Ion Nechita (Univ. Touloouse and CNRS) DTSTART:20210609T140000Z DTEND:20210609T144500Z DTSTAMP:20260404T095208Z UID:Opalg21/7 DESCRIPTION:Title: Enumerating meanders - three perspectives\nby Ion Nechita (Univ . Touloouse and CNRS) as part of Conference on operator algebras and relat ed topics in Istanbul\, 2021\n\n\nAbstract\nThe problem of enumerating mea nders is a long-standing open problem in combinatorics. Many different tec hniques have been used to provide bounds on the asymptotic growth rate of the number of meanders. Here\, we present some of the old methods and some new ones\, coming from three (related) points of view. First\, as noted b y Fukuda and Sniady\, meanders appear in relation to the partial transposi tion operation in quantum information theory. A second model for meandric numbers comes from random matrix theory: we shall review some old models d ue to di Francesco and present some new ones. Finally\, I shall present a joint work with Motohisa Fukuda (arXiv:1609.02756 and arXiv:2103.03615) on a third point of view\, that of non-commutative probability. Using the op erations of free and boolean moment-cumulant transforms\, we enumerate lar ge sub-classes of meanders\, generalizing previous work of Goulden\, Nica\ , and Puder.\n LOCATION:https://stable.researchseminars.org/talk/Opalg21/7/ END:VEVENT BEGIN:VEVENT SUMMARY:Alice Guionnet (ENS Lyon) DTSTART:20210609T150000Z DTEND:20210609T155000Z DTSTAMP:20260404T095208Z UID:Opalg21/8 DESCRIPTION:Title: Topological expansions\, Random matrices and free probability\n by Alice Guionnet (ENS Lyon) as part of Conference on operator algebras an d related topics in Istanbul\, 2021\n\n\nAbstract\nIn this lecture\, I wil l discuss the remarkable connection between random matrices\, the enumerat ion of maps and some applications to operator algebras and physics. This t alk will be based on joint works with Vaughan Jones and Dima Shlyakhtenko as well as work in progress with Edouard Maurel Segala.\n LOCATION:https://stable.researchseminars.org/talk/Opalg21/8/ END:VEVENT BEGIN:VEVENT SUMMARY:Gilles Pisier (Texas A&M) DTSTART:20210609T160000Z DTEND:20210609T165000Z DTSTAMP:20260404T095208Z UID:Opalg21/9 DESCRIPTION:Title: From injectivity to approximation properties for von Neumann algebr as\nby Gilles Pisier (Texas A&M) as part of Conference on operator alg ebras and related topics in Istanbul\, 2021\n\n\nAbstract\nA von Neumann a lgebra M is called injective if there is a projection P:B(H) -> M with ||P ||= 1. This is the analogue for von Neumann algebras of amenability for di screte groups\, and it notoriously fails when M = M(F) is the von Neumann algebra of a non-commutative free group F. We will introduce the class of ''seemingly injective'' von Neumann algebras. This includes M(F). We show that M is seemingly injective iff it has the (matricial) weak* positive me tric approximation property (AP in short). This is parallel to Connes's ch aracterization of injectivity by the weak* completely positive AP. We show that M(F) is isomorphic to B(H) as Banach spaces when F is countable. Las tly we discuss several open questions that might be related to Kazhdan's p roperty (T) for groups.\n LOCATION:https://stable.researchseminars.org/talk/Opalg21/9/ END:VEVENT BEGIN:VEVENT SUMMARY:Kristan Temme (IBM Research) DTSTART:20210609T173000Z DTEND:20210609T181500Z DTSTAMP:20260404T095208Z UID:Opalg21/10 DESCRIPTION:by Kristan Temme (IBM Research) as part of Conference on opera tor algebras and related topics in Istanbul\, 2021\n\nAbstract: TBA\n LOCATION:https://stable.researchseminars.org/talk/Opalg21/10/ END:VEVENT BEGIN:VEVENT SUMMARY:Nikhil Srivastava (UC Berkeley) DTSTART:20210609T183000Z DTEND:20210609T191500Z DTSTAMP:20260404T095208Z UID:Opalg21/11 DESCRIPTION:Title: Quantitative Diagonalizability\nby Nikhil Srivastava (UC Berke ley) as part of Conference on operator algebras and related topics in Ista nbul\, 2021\n\n\nAbstract\nA diagonalizable matrix has linearly independen t eigenvectors. Since the set of non diagonalizable matrices has measure z ero\, every matrix is a limit of diagonalizable matrices. We prove a quant itative version of this fact: every n x n complex matrix is within distanc e delta in the operator norm of a matrix whose eigenvectors have condition number poly(n)/delta\, confirming a conjecture of E. B. Davies. The proof is based adding a complex Gaussian perturbation to the matrix and studyin g its pseudospectrum. Joint work with J. Banks\, A. Kulkarni\, S. Mukherje e\n LOCATION:https://stable.researchseminars.org/talk/Opalg21/11/ END:VEVENT BEGIN:VEVENT SUMMARY:Anna Jencova (Slovakian Academy of Sciences) DTSTART:20210610T130000Z DTEND:20210610T134500Z DTSTAMP:20260404T095208Z UID:Opalg21/12 DESCRIPTION:Title: Renyi relative entropies and noncommutative Lp spaces\nby Anna Jencova (Slovakian Academy of Sciences) as part of Conference on operator algebras and related topics in Istanbul\, 2021\n\n\nAbstract\nThere are s everal quantum versions of the Renyi relative entropies\, which are fundam ental in quantum information theory. Some of these quantities were extende d to the general context of normal states of a von Neumann algebra. We con centrate on the class of sandwiched quantum Renyi relative entropies. We s how that this class can be defined in terms of the interpolation Lp spaces due to Kosaki. We discuss some properties of these quantities\, especiall y the connection to the Araki relative entropy and the data processing ine quality (monotonicity) with respect to positive unital normal maps. In the second part of the talk\, it is shown that reversibility of a 2-positive unital normal map with respect to a set of normal states is characterized by equality in the data processing inequality.The talk is based on the pap ers A. Jencova: Renyi relative entropies and noncommutative Lp spaces I an d II\, Annales H. Poincare\, 2018 and 2021 (to appear).\n LOCATION:https://stable.researchseminars.org/talk/Opalg21/12/ END:VEVENT BEGIN:VEVENT SUMMARY:Fabio Cipriani (Politechnic Milano) DTSTART:20210610T140000Z DTEND:20210610T144500Z DTSTAMP:20260404T095208Z UID:Opalg21/13 DESCRIPTION:Title: KMS Dirichlet forms\, coercivity and superbounded Markovian semigr oups\nby Fabio Cipriani (Politechnic Milano) as part of Conference on operator algebras and related topics in Istanbul\, 2021\n\n\nAbstract\nWe provide a new construction of Dirichlet forms on von Neumann algebras asso ciated to eigenvalues of the modular operator of f.n. non tracial states. We describe their structure in terms of derivations and prove coercivity b ounds\, from which the spectral growth rate are derived. We also introduce a regularizing property of Markovian semigroups (superboundedness) strong er than hypercontractivity\, in terms of noncommutative Lp(M)spaces. We al so prove superboundedness for the Markovian semigroups associated to the c lass of Dirichlet forms introduced above\, for type I factors M. We then a pply this tools to provide a general construction of the quantum Ornstein- Uhlembeck semigroups of the CCR and some of their non-perturbative deforma tions.\n LOCATION:https://stable.researchseminars.org/talk/Opalg21/13/ END:VEVENT BEGIN:VEVENT SUMMARY:Joachim Cuntz (Univ. Muenster) DTSTART:20210610T150000Z DTEND:20210610T155000Z DTSTAMP:20260404T095208Z UID:Opalg21/14 DESCRIPTION:Title: C*-algebras generated by isometries.\nby Joachim Cuntz (Univ. Muenster) as part of Conference on operator algebras and related topics in Istanbul\, 2021\n\n\nAbstract\nThe property of an operator s on a Hilbert space to be isometric can be characterized by the algebraic condition s*s = 1. Many interesting and important C*-algebras can be generated byÂ is ometries or obtained by constructions involving isometries. We give a (par tly historical) survey of various results in which the author has been inv olved and which are based on such constructions.\n LOCATION:https://stable.researchseminars.org/talk/Opalg21/14/ END:VEVENT BEGIN:VEVENT SUMMARY:George Elliott (Univ. Toronto) DTSTART:20210610T160000Z DTEND:20210610T165000Z DTSTAMP:20260404T095208Z UID:Opalg21/15 DESCRIPTION:Title: The classification of well-behaved simple C*-algebras\nby Geor ge Elliott (Univ. Toronto) as part of Conference on operator algebras and related topics in Istanbul\, 2021\n\n\nAbstract\nA brief survey will be gi ven of the classification of simple separable amenable C* algebras which a re Jiang-Su stable and (possibly redundant) satisfy the Universal Coeffici ent Theorem (UCT). There are many examples of such algebras\, but note tha t\, if a given simple UCT separable amenable C* algebra is not known to be stable under tensoring with the Jiang-Su algebra\, this is assured just b y tensoring it anyway with this algebra. Furthermore\, the invariant can b e formulates in a way that is insensitive to this operation. (Of course\, it is only complete after tenderization).\n LOCATION:https://stable.researchseminars.org/talk/Opalg21/15/ END:VEVENT BEGIN:VEVENT SUMMARY:Kristin Courtney (Univ. Muenster) DTSTART:20210610T173000Z DTEND:20210610T181500Z DTSTAMP:20260404T095208Z UID:Opalg21/16 DESCRIPTION:Title: Nuclearity and generalized inductive limits\nby Kristin Courtn ey (Univ. Muenster) as part of Conference on operator algebras and related topics in Istanbul\, 2021\n\n\nAbstract\nOne of Alain Connes' seminal res ults establishes that any semi-discrete (or injective or amenable) von Neu mann algebra can be written as a direct limit of dimensional von Neumann a lgebras. In the C*-setting however\, such a concise characterization is no t possible: the direct C*-analogue of semi-discreteness is nuclearity\, an d most nuclear C*-algebras do not arise as the direct limits of finite dim ensional C*-algebras. Nonetheless\, by generalizing the notion of inductiv e limits of C*-algebras\, Blackadar and Kirchberg were able to characteriz e quasidiagonal nuclear C*-algebras as those arising as (generalized) indu ctive limits of finite dimensional C*-algebras. In joint work with Wilhelm Winter\, we give a further generalization of this construction\, which gi ves us a complete characterization of separable nuclear C*-algebras as tho se arising from a (generalized) inductive limit of finite dimensional C*-a lgebras.\n LOCATION:https://stable.researchseminars.org/talk/Opalg21/16/ END:VEVENT BEGIN:VEVENT SUMMARY:Ryszard Nest (Univ. Copenhagen) DTSTART:20210610T183000Z DTEND:20210610T191500Z DTSTAMP:20260404T095208Z UID:Opalg21/17 DESCRIPTION:Title: Projective representations of compact quantum groups and the quant um assembly map\nby Ryszard Nest (Univ. Copenhagen) as part of Confere nce on operator algebras and related topics in Istanbul\, 2021\n\n\nAbstra ct\nThe torsion phenomena play important role in the construction of the a ssembly map in the context of Baum-Connes conjecture. The corresponding ca se of quantum groups is more involved\, since the torsion phenomena are no t necessarily associated to torsion subgroups.An important role in this co ntext is played by projective representations of quantum groups. We will d escribe the general structure of projective representations\, associated t wisted group C*-algebras and the related torsion phenomena for compact qua ntum groups.We will also describe the role that these results play in the context of the assembly map for compact quantum groups.This is ''work in p rogress'' joint with Kenny De Commer and Ruben Martos.\n LOCATION:https://stable.researchseminars.org/talk/Opalg21/17/ END:VEVENT END:VCALENDAR