BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Drupal iCal API//EN X-WR-CALNAME:Events items teaser BEGIN:VEVENT UID:63d48133169aa DTSTART;TZID=America/Toronto:20230203T150000 SEQUENCE:0 TRANSP:TRANSPARENT DTEND;TZID=America/Toronto:20230203T160000 SUMMARY:Non-commutative measure theory CLASS:PUBLIC DESCRIPTION:Summary \n\nROBERT MARTIN\, UNIVERSITY OF MANITOBA\n\nMeasure t heory on the complex unit circle and analytic function theory\nin the unit disk\, in particular the theory of Hardy spaces\, are\nfundamentally conn ected. Several celebrated theorems due to P. Fatou\,\nG. Herglotz\, F. and M. Riesz and G. Szego describe the relationship\nbetween these theories. We will show that many of these classical\nresults have natural extensions to the multivariate and\nnon-commutative settings of the full Fock space\ , or free Hardy space\nof square–summable power series in several non-co mmuting variables\nand positive non-commutative (NC) measures. Here a (pos itive) NC\nmeasure is any positive linear functional on the free disk syst em\, the\noperator system generated by the left creation operators\, which act as\nleft multiplication by the independent NC variables on the free H ardy\nspace. We will focus on a recently established NC Szego theorem and\ nits consequences.\n\nThis seminar will be held both online and in person: \n\n* Room: MC 5479\n * Zoom link:\n 4?pwd=NGpLM3B4eWNZckd1aTROcmRreW96QT09\n\n DTSTAMP:20230128T015811Z END:VEVENT BEGIN:VEVENT UID:63d4813317983 DTSTART;TZID=America/Toronto:20230126T160000 SEQUENCE:0 TRANSP:TRANSPARENT DTEND;TZID=America/Toronto:20230126T170000 SUMMARY:Amenability and stability for discrete groups CLASS:PUBLIC DESCRIPTION:Summary \n\nERIK SEGUIN\, DEPARTMENT OF PURE MATHEMATICS\, UNIV ERSITY OF WATERLOO\n\nThe notion of a representation of a group on a Hilbe rt space can be\ngeneralized to that of an \"approximate representation\"\ , in which the\nusual homomorphism condition is replaced by some bound on the norm\ndistance between the operators φ(xy) and φ(x) φ(y). It is nat ural\nto ask about the stability of this class of maps: namely\, when the\ ndefect of an approximate representation is small\, is the approximate\nre presentation well-approximated by a genuine representation of the\ngroup? In this talk\, we explore the connection between amenability and\nthe stab ility of approximate representations for discrete groups. \n\nThis semina r will be held both online and in person:\n\n* Room: MC 5479\n * Zoom link :\n 6QT09\n[ RreW96QT09]\n\n DTSTAMP:20230128T015811Z END:VEVENT BEGIN:VEVENT UID:63d48133180a6 DTSTART;TZID=America/Toronto:20230119T160000 SEQUENCE:0 TRANSP:TRANSPARENT DTEND;TZID=America/Toronto:20230119T170000 SUMMARY:The K-theory of a rational function CLASS:PUBLIC DESCRIPTION:Summary \n\nJEREMY HUME\, UNIVERSITY OF GLASGOW\n\nThe dynamics of iterating a rational function exhibits complicated and\ninteresting be haviour when restricted to points in its Julia set.\nKajiwara and Watatani constructed a C*-algebra from a rational\nfunction restricted to its Juli a set in order to study its dynamics\nfrom an operator algebra perspective . They showed the C*-algebras are\nKirchberg algebras that satisfy the UCT \, and are therefore classified\nby K-theory. The K-theory groups of these algebras have been computed\nin some special cases\, for instance by Nekr ashevych in the case of a\nhyperbolic and post-critically finite rational function. We compute\nthe K-theory groups for a general rational function using methods\ndifferent to those used before. In this talk\, we discuss o ur methods\nand results\, including new topological conjugacy invariants f or a\nrational function restricted to its Julia set.\n\nThis seminar will be held both online and in person:\n\n* Room: MC 5479\n * Zoom link:\nhttp s://\n \n DTSTAMP:20230128T015811Z END:VEVENT BEGIN:VEVENT UID:63d481331867a DTSTART;TZID=America/Toronto:20220202T160000 SEQUENCE:0 TRANSP:TRANSPARENT DTEND;TZID=America/Toronto:20220202T160000 SUMMARY:Q-systems and higher unitary idempotent completion for C*-algebras CLASS:PUBLIC DESCRIPTION:Summary \n\nROBERTO HERNANDEZ-PALOMARES\, TEXAS A&M UNIVERSITY\ n\nQ-systems were introduced by Longo to study finite index inclusions of\ ninfinite von Neumann factors. A Q-system is a unitary version of a\nFrobe nius algebra object in a tensor category or a C* 2-category. By\nwork of M üger\, Q-systems give an axiomatization of the standard\ninvariant of a f inite index subfactor.\n DTSTAMP:20230128T015811Z END:VEVENT BEGIN:VEVENT UID:63d48133191b2 DTSTART;TZID=America/Toronto:20220119T160000 SEQUENCE:0 TRANSP:TRANSPARENT DTEND;TZID=America/Toronto:20220119T160000 SUMMARY:Spectral bounds for chromatic number of quantum graphs CLASS:PUBLIC DESCRIPTION:Summary \n\nPRIYANGA GANESAN\, TEXAS A&M UNIVERSITY\n DTSTAMP:20230128T015811Z END:VEVENT BEGIN:VEVENT UID:63d4813319733 DTSTART;TZID=America/Toronto:20220112T160000 SEQUENCE:0 TRANSP:TRANSPARENT DTEND;TZID=America/Toronto:20220112T160000 SUMMARY:Non-crossing Partitions and the Infinitesimal Law of Real Wishart\n Random Matrices CLASS:PUBLIC DESCRIPTION:Summary \n\nJAMIE MINGO\, QUEEN'S UNIVERSITY\n\nIn 1973 G. 't H ooft considered \"gauge theory with colour gauge group\nU(N) and quarks ha ving a colour index from 1 to N''. He showed that in\nthe limit N tends to infinity \"only planar diagrams with quarks at the\nedges dominate''. In 1991 D. Voiculescu showed that\, also in the\nlimit N tends to infinity\ , free probability described the behaviour\nof independent and unitarily i nvariant matrix ensembles. In 1994 R.\nSpeicher tied these together when h e showed that free independence\ncould be described with non-crossing diag rams. \n DTSTAMP:20230128T015811Z END:VEVENT BEGIN:VEVENT UID:63d4813319ce0 DTSTART;TZID=America/Toronto:20211201T160000 SEQUENCE:0 TRANSP:TRANSPARENT DTEND;TZID=America/Toronto:20211201T160000 SUMMARY:Noncommutative Nullstellensatz and Perfect Games CLASS:PUBLIC DESCRIPTION:Summary \n\nADAM BENE WATTS\, INSTITUTE OF QUANTUM COMPUTING\, UNIVERSITY OF\nWATERLOO\n\nThe foundations of classical Algebraic Geometry and Real Algebraic\nGeometry are the Nullstellensatz and Positivstellensa tz. Over the last\ntwo decades the basic analogous theorems for matrix and operator\ntheory (noncommutative variables) have emerged. In this talk I' ll\ndiscuss commuting operator strategies for nonlocal games\, recall NC\n Nullstellensatz which are helpful\, and then apply them to a very broad\nc ollection of nonlocal games.\n DTSTAMP:20230128T015811Z END:VEVENT BEGIN:VEVENT UID:63d481331a315 DTSTART;TZID=America/Toronto:20211126T160000 SEQUENCE:0 TRANSP:TRANSPARENT DTEND;TZID=America/Toronto:20211126T160000 SUMMARY:Applications of graph coloring games to quantum automorphism groups CLASS:PUBLIC DESCRIPTION:Summary \n\nSAMUEL HARRIS\, TEXAS A&M UNIVERSITY\n DTSTAMP:20230128T015811Z END:VEVENT BEGIN:VEVENT UID:63d481331a9b5 DTSTART;TZID=America/Toronto:20211117T160000 SEQUENCE:0 TRANSP:TRANSPARENT DTEND;TZID=America/Toronto:20211117T160000 SUMMARY:Zappa-Szep product\, self-similar action\, and equivalent groupoids CLASS:PUBLIC DESCRIPTION:Summary \n\nBOYU LI\, UNIVERSITY OF WATERLOO AND UNIVERSITY OF WINDSOR\n DTSTAMP:20230128T015811Z END:VEVENT BEGIN:VEVENT UID:63d481331af4b DTSTART;TZID=America/Toronto:20211110T160000 SEQUENCE:0 TRANSP:TRANSPARENT DTEND;TZID=America/Toronto:20211110T160000 SUMMARY:Free Stein Dimension CLASS:PUBLIC DESCRIPTION:Summary \n\nBRENT NELSON\, MICHIGAN STATE UNIVERSITY\n DTSTAMP:20230128T015811Z END:VEVENT END:VCALENDAR