BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Drupal iCal API//EN X-WR-CALNAME:Events items teaser X-WR-TIMEZONE:America/Toronto BEGIN:VTIMEZONE TZID:America/Toronto X-LIC-LOCATION:America/Toronto BEGIN:DAYLIGHT TZNAME:EDT TZOFFSETFROM:-0500 TZOFFSETTO:-0400 DTSTART:20260308T070000 END:DAYLIGHT BEGIN:STANDARD TZNAME:EST TZOFFSETFROM:-0400 TZOFFSETTO:-0500 DTSTART:20251102T060000 END:STANDARD END:VTIMEZONE BEGIN:VEVENT UID:69f545810b97a DTSTART;TZID=America/Toronto:20260505T093000 SEQUENCE:0 TRANSP:TRANSPARENT DTEND;TZID=America/Toronto:20260505T123000 URL:https://uwaterloo.ca/pure-mathematics/events/phd-defence-2 SUMMARY:PhD Defence CLASS:PUBLIC DESCRIPTION:JENNIFER ZHU\, UNIVERSITY OF WATERLOO\n\n_Categorical Limits o f Quantum Graphs and Possibilities Induced by\nQuantumPseudometrics_\n\nQu antum graphs and quantum pseudometrics as defined by Kuperberg and\nWeaver have roots in quantum errorcorrection but have since been\ndeveloped as s ubjects in their own right. The motivation for the first\nhalf of thisthes is is to build an infinite quantum graph from finite\nquantum graphs. The latter have been subjected to fargreater scrutiny\ndue to their connection s to categorical quantum theory\, while the\nformer have been somewhatnegl ected. To be precise\, we define and take\nthe categorical (co)limit of qu antum graphs by developing a newnotion\nof morphism compatible with previo us notions but carrying less\nbaggage. The inspiration for the secondhalf follows from the\n(unpublished) theorem that pure states on a von Neumann algebra\n\\mathcal{M} are givenby maximal filters in the projection lattic e of\n\\mathcal{M}. Upon the observation that points in a metric space$(X\ ,\nd)$ with topology $\\tau$ are also given by maximal filters $\\tau$ and \nthat quantum pseudometrics provide anotion of distance between\nprojecti ons in $B(\\ell^2) \\overline{\\otimes} \\mathcal M$\, we are led\nto a no tion ofdistance $f$ between pure states induced by these\nquantum pseudome trics. Also this function $f$ does not satisfythe\ntriangle inequality\, w e make some parallels between it and David\nLewis's conception of ``possib le worlds.''\n\nMC 2009 DTSTAMP:20260502T002953Z END:VEVENT BEGIN:VEVENT UID:69f545810dc1e DTSTART;TZID=America/Toronto:20260505T150000 SEQUENCE:0 TRANSP:TRANSPARENT DTEND;TZID=America/Toronto:20260505T160000 URL:https://uwaterloo.ca/pure-mathematics/events/analysis-seminar-217 SUMMARY:Analysis Seminar CLASS:PUBLIC DESCRIPTION:PAUL SKOUFRANISYORK UNIVERSITY\n\n_Non-Commutative Majorization _\n\nThe maps that send a self-adjoint matrix $A$ to $U^*AU$ where $U$ is a\nunitary matrix are essential inQuantum Information Theory as these\nmap s transmit quantum information in a reversible way. When\nconvexcombinatio ns of such maps are taken\, one obtains what are known\nas the mixed unita ry quantum channels\, whichare essential models for\nhow quantum informati on can be transmitted when noise is present. Just\nas the unitaryconjugate s of a self-adjoint matrix can be determined\nvia spectral data\, so too c an the image of a self-adjointmatrix under\nall possible mixed unitary qua ntum channels. Since this is equivalent\nto characterizing the convexhull of the unitary orbit of a\nself-adjoint matrix\, this problem has a well-k nown solution from\noperator theoryinvolving the notion of matrix majoriza tion of one\nself-adjoint operator by another. In this talk\, we will exam inehow we\ncan extend the notion of matrix majorization to non-commutative \ncontexts. In particular\, we will discussa notion of non-commutative\nma jorization that characterizes the potential outputs under all\nquantum cha nnels ofany non-commutative tuple of matrices. This is\nbased on joint wor k with Matt Kennedy.\n\nMC 5417 or Join on Zoom\n[https://uwaterloo.zoom.u s/j/94186354814?pwd=NGpLM3B4eWNZckd1aTROcmRreW96QT09] DTSTAMP:20260502T002953Z END:VEVENT BEGIN:VEVENT UID:69f545810e552 DTSTART;TZID=America/Toronto:20260330T130000 SEQUENCE:0 TRANSP:TRANSPARENT DTEND;TZID=America/Toronto:20260330T143000 URL:https://uwaterloo.ca/pure-mathematics/events/computability-learning-sem inar-168 SUMMARY:Computability Learning Seminar CLASS:PUBLIC DESCRIPTION:WILLIAM DAN\, UNIVERSITY OF WATERLOO\n\n_Solovay Reducibility_\ n\nHaving discussed the relationship between Solovay reducibility and the\ nnewly introduced reducibilities\, K-reducibility and C-reducibility\, we\ nturn back to study its relationship with previously discussed\nreducibili ties\, Turing reducibility and wtt-reducibility. Then\, if\ntime permits\, we will completely finish sections 9.1 and 9.2 by\ndiscussing a final cha racterization of Solovay reducibility and going\nbeyond random left-c.e. r eals to look at random left-d.c.e. reals.\n\nMC 5403 DTSTAMP:20260502T002953Z END:VEVENT BEGIN:VEVENT UID:69f545810ed5a DTSTART;TZID=America/Toronto:20260324T160000 SEQUENCE:0 TRANSP:TRANSPARENT DTEND;TZID=America/Toronto:20260324T170000 URL:https://uwaterloo.ca/pure-mathematics/events/model-theory-working-semin ar-42 SUMMARY:Model Theory Working Seminar CLASS:PUBLIC DESCRIPTION:FATEME PEIMANY\, UNIVERSITY OF WATERLOO\n\n_Strongly minimal gr oups in CCM_\n\nWe continue our study of the structure of groups definable in CCM\, now\nin our second session on this topic\, withthe goal of provi ng that\nevery strongly minimal group is either a complex torus or a\n(com mutative) linearalgebraic group.\n\nMC 5479 DTSTAMP:20260502T002953Z END:VEVENT BEGIN:VEVENT UID:69f545810f4b0 DTSTART;TZID=America/Toronto:20260326T143000 SEQUENCE:0 TRANSP:TRANSPARENT DTEND;TZID=America/Toronto:20260326T154500 URL:https://uwaterloo.ca/pure-mathematics/events/differential-geometry-work ing-seminar-182 SUMMARY:Differential Geometry Working Seminar CLASS:PUBLIC DESCRIPTION:SPENCER KELLY\, UNIVERSITY OF WATERLOO\n\n_Constructing a Slice Theorem in Infinite Dimensions_\n\nThe slice theorem is a powerful tool f or understanding proper group\nactions on manifolds\; however it does noth old on infinite dimensional\nmanifolds\, nor does there exist a general in finite dimensional\nextension of it.However\, on specific infinite dimensi onal manifolds\,\nworking on a case-by-case basis\, we have been able toco nstruct\nanalogues of the slice theorem. In this talk\, we will investigat e one\nof these cases\, namely the space ofconnections on a bundle over a\ ncompact Riemannian manifold\, acted on by the gauge group.\n\nMC 5403 DTSTAMP:20260502T002953Z END:VEVENT BEGIN:VEVENT UID:69f545810fc17 DTSTART;TZID=America/Toronto:20260323T130000 SEQUENCE:0 TRANSP:TRANSPARENT DTEND;TZID=America/Toronto:20260323T143000 URL:https://uwaterloo.ca/pure-mathematics/events/computability-learning-sem inar-167 SUMMARY:Computability Learning Seminar CLASS:PUBLIC DESCRIPTION:WILLIAM DAN\, UNIVERSITY OF WATERLOO\n\n_Solovay Reducibility a nd Relative Randomness_\n\nHaving completed our characterization of left-c .e. random reals\, we\nreturn to the concept of Solovay reducibilityto stu dy it more deeply.\nWe will see that beyond the characterizations we have seen so far\,\nSolovay reducibilitycan be viewed as a measure of relative randomness\,\nand connect this perspective back to the Kucera-Slamantheore m. We will\nalso relate it to the reducibilities we have studied previousl y\, and\ngive a final\, possiblysimplest\, characterization of Solovay\nre ducibility. This seminar follows sections 9.1 and 9.2 from the\nDowneyand Hirschfeldt book.\n\nMC 5403 DTSTAMP:20260502T002953Z END:VEVENT BEGIN:VEVENT UID:69f54581103bb DTSTART;TZID=America/Toronto:20260317T160000 SEQUENCE:0 TRANSP:TRANSPARENT DTEND;TZID=America/Toronto:20260317T170000 URL:https://uwaterloo.ca/pure-mathematics/events/model-theory-working-semin ar-41 SUMMARY:Model Theory Working Seminar CLASS:PUBLIC DESCRIPTION:FATEME PEIMANY\, UNIVERSITY OF WATERLOO\n\n_Definable groups in CCM_\n\nWe continue to study the structure of groups definable in CCM\, t oward\nshowing that every strongly minimal group is either a complex torus or\na (commutative) linear algebraic group.\n\nMC 5479 DTSTAMP:20260502T002953Z END:VEVENT BEGIN:VEVENT UID:69f5458110b82 DTSTART;TZID=America/Toronto:20260319T143000 SEQUENCE:0 TRANSP:TRANSPARENT DTEND;TZID=America/Toronto:20260319T154500 URL:https://uwaterloo.ca/pure-mathematics/events/differential-geometry-work ing-seminar-181 SUMMARY:Differential Geometry Working Seminar CLASS:PUBLIC DESCRIPTION:VIKTOR MAJEWSKI\, UNIVERSITY OF WATERLOO\n\n_Filling Holes in t he Spin(7)-Teichmüller Space and String\nCohomology_\n\nIn this talk\, I apply the analytic results from the first talk to\nstudy the boundary of t he Spin(7) Teichmüller space.Using compactness\nresults for Ricci-flat me trics together with known examples of Spin(7)\nmanifolds\, it is knownthat Spin(7) orbifolds with SU(N) isotropy arise\nas boundary points of the mo duli space. Building on theresolution\nscheme for Spin(7) orbifolds that I discussed in 2024\, and which I\nwill briefly review\, we show howthis bo undary can be removed by\nrequiring Spin(7) orbifolds to encode informatio n about their\nresolutions. Inthis way\, the Teichmüller space is enlarge d to include\norbifold limits together with their compatible resolutions\, thereby\nfilling in the boundary. Finally\, we explain how this perspectiv e is\nrelated to a Spin(7) analogue of thecrepant resolution conjecture fr om\nstring cohomology\, providing a geometric interpretation of the\nobstr uctioncomplex discussed in the linear gluing analysis in the\nfirst talk.\ n\nMC 5403 DTSTAMP:20260502T002953Z END:VEVENT BEGIN:VEVENT UID:69f5458111348 DTSTART;TZID=America/Toronto:20260310T160000 SEQUENCE:0 TRANSP:TRANSPARENT DTEND;TZID=America/Toronto:20260310T170000 URL:https://uwaterloo.ca/pure-mathematics/events/model-theory-working-semin ar-40 SUMMARY:Model Theory Working Seminar CLASS:PUBLIC DESCRIPTION:FATEME PEIMANY\, UNIVERSITY OF WATERLOO\n\n_Model Theory Workin g Seminar: Definable groups in CCM_\n\nWe continue to study the structure of groups definable in CCM\, toward\nshowing that every strongly minimal g roup is either a complex torus or\na (commutative) linear algebraic group. \n\nMC 5479 DTSTAMP:20260502T002953Z END:VEVENT BEGIN:VEVENT UID:69f5458111ac9 DTSTART;TZID=America/Toronto:20260312T150000 SEQUENCE:0 TRANSP:TRANSPARENT DTEND;TZID=America/Toronto:20260312T153000 URL:https://uwaterloo.ca/pure-mathematics/events/differential-geometry-work ing-seminar-180 SUMMARY:Differential Geometry Working Seminar CLASS:PUBLIC DESCRIPTION:AMANDA PETCU\, UNIVERSITY OF WATERLOO\n\n_Some results on hype rsymplectic structures_\n\nA conjecture of Simon Donaldson is that on a co mpact 4-manifold X^4\none can flow from a hypersymplectic structure to a h yperkahler\nstructure while remaining in the same cohomology class. To thi s end\nthe hypersymplectic flow was introduced by Fine-Yao. In this thesis \nthe notion of a positive triple on X^4 is used to define a\nhypersymplec tic and hyperkahler structure. Given a closed positive\ntriple one can def ine either a closed G2 structure or a coclosed G2\nstructure on T^3 x X^4. The coclosed G2 structure is evolved under the\nG2 Laplacian coflow. This descends to a flow of the positive triple on\nX^4\, which is again the Fi ne-Yao hypersymplectic flow. In the second\npart of this thesis we let X^4 = R^4 \\0 with a particular\ncohomogeneity one action. A hypersymplectic structure invariant under\nthis action is introduced. The Riemann and Ricc i curvature tensors are\ncomputed and we verify in a particular case that this hypersymplectic\nstructure can be transformed to a hyperkahler struct ure. The notion of\na soliton for the hypersymplectic flow in this particu lar case is\nintroduced and it is found that steady solitons give rise to\ nhypersymplectic structures that can be transformed to hyperkahler\nstruct ures. Some other soliton solutions are also discussed.\n\nMC 5403 DTSTAMP:20260502T002953Z END:VEVENT END:VCALENDAR