{"id":18,"date":"2021-04-16T10:41:38","date_gmt":"2021-04-16T10:41:38","guid":{"rendered":"https:\/\/www.mi.uni-koeln.de\/RepTheory\/?page_id=18"},"modified":"2025-09-12T06:40:29","modified_gmt":"2025-09-12T06:40:29","slug":"forschungsseminar","status":"publish","type":"page","link":"https:\/\/www.mi.uni-koeln.de\/RepTheory\/forschungsseminar\/","title":{"rendered":"Research seminars"},"content":{"rendered":"\n<script src=\"https:\/\/polyfill.io\/v3\/polyfill.min.js?features=es6\"><\/script>\n\t<script id=\"MathJax-script\" async=\"\" src=\"https:\/\/cdn.jsdelivr.net\/npm\/mathjax@3\/es5\/tex-mml-chtml.js\"><\/script>\n\n\n\n<h3>Seminare und Vortr\u00e4ge im WS 2025\/2026<\/h3>\n\n\n\n<table id=\"tablepress-15\" class=\"tablepress tablepress-id-15\">\n<thead>\n<tr class=\"row-1 odd\">\n\t<th class=\"column-1\" style=\"width:13%;\">Date<\/th><th class=\"column-2\" style=\"width:25%;\">Lecturer<\/th><th class=\"column-3\" style=\"width:20%;\">Seminar<\/th><th class=\"column-4\" style=\"width:20%;\">Theme<\/th><th class=\"column-5\" style=\"width:20%;\">Time<\/th><th class=\"column-6\" style=\"width:7%;\">Location<\/th>\n<\/tr>\n<\/thead>\n<tbody class=\"row-hover\">\n<tr class=\"row-2 even\">\n\t<td class=\"column-1\">28 Jan 2026<\/td><td class=\"column-2\">\u00c1lvaro S\u00e1nchez   (Universidad de Murcia, Spain) <\/td><td class=\"column-3\"><\/td><td class=\"column-4\">Abstract representation theory of quivers and spectral Picard groups<br \/>\n<br \/>\nAbstract. While the (derived) representation theory of quivers over a field is by now well-understood, much less is known when moving to coefficients in the integers or an arbitrary commutative ring. In this talk, we take a rather radical but well-founded approach: it has recently been observed that certain well-known symmetries of categories of representations (tilting results) are actually mere consequences of the stability of the coefficients involved, and so they exist in a much broader generality, often for the corresponding representations in any stable homotopy theory \u2014 this includes arbitrary rings, schemes, dg algebras, or ring spectra. For a finite acyclic quiver Q, we present here a method for producing universal autoequivalences of representations C^Q in any stable \u221e-category C, which are the elements of the spectral Picard group of Q. This is based on an abstract equivalence of C^Q with a certain mesh \u221e-category of representations of the Auslander\u2013Reiten quiver \u0393_Q. Then our universal equivalences arise from symmetries of \u0393_Q, and thus yield abstract versions of key functors in classical representation theory \u2014 e.g. the Auslander-Reiten translation, the Serre functor, etc. Moreover, for representations of trees this allows us to realize the whole derived Picard group over a field as a factor of the spectral Picard group.<\/td><td class=\"column-5\">Wednesday, 2pm\u20133pm<br \/>\nTime Zone Berlin, Rome, Paris<br \/>\n<\/td><td class=\"column-6\">Register here to obtain the Zoom link:<br \/>\nhttps:\/\/sites.google.com\/view\/lagoonwebinar\/home<\/td>\n<\/tr>\n<tr class=\"row-3 odd\">\n\t<td class=\"column-1\">03 Feb 2026<\/td><td class=\"column-2\">Juan Omar G\u00f3mez Rodr\u00edguez <br \/>\n(Universit\u00e4t Bielefeld) <\/td><td class=\"column-3\"><\/td><td class=\"column-4\">Conservativity via purity in tensor triangulated categories<br \/>\n<br \/>\nAbstract: Given a family of coproduct-preserving tensor-triangulated (tt) functors between rigidly-compactly generated tt-categories, it is natural to ask when they are jointly conservative. Such joint conservativity is the minimal requirement for attempting to descend tt-geometric information along the family. In this talk, I will present a criterion for determining when a family of geometric functors is jointly conservative through the lens of purity in compactly generated triangulated categories, highlighting its homological flavor. We introduce the notion of pure descendability and we apply it to two particular situations involving sequential limits of ring spectra. The talk is based on joint work with Natalia Castellana. <\/td><td class=\"column-5\">Tuesday, 2pm (CEST) in person\t<\/td><td class=\"column-6\">Stefan-Cohn-Vossen-Raum <br \/>\nMathematik (Raum 313)<\/td>\n<\/tr>\n<tr class=\"row-4 even\">\n\t<td class=\"column-1\">25 Feb 2026<\/td><td class=\"column-2\">Tristan Bozec<br \/>\n(Universit\u00e9 Angers, France)<\/td><td class=\"column-3\"><\/td><td class=\"column-4\">Abstract. One very nice feature of derived algebraic geometry, and specifically shifted symplectic geometry, is how convenient it is to tackle topological field theories. We will first review the recent history of this approach, through the fundamental use of mapping stacks and the Betti shape. We will illustrate our review with many very concrete examples and noncommutative applications, before explaining how the (recently proved) Moore\u2013Tachikawa conjecture leads us to considering the Dolbeault shape in view of defining a new TFT associated to Higgs fields. This reports an ongoing collaboration with Damien Calaque, Julien Grivaux and Hugo Pourcelot.<\/td><td class=\"column-5\">Wednesday, 2pm\u20133pm<br \/>\nTime Zone Berlin, Rome, Paris<br \/>\n<\/td><td class=\"column-6\">Register here to obtain the Zoom link:<br \/>\nhttps:\/\/sites.google.com\/view\/lagoonwebinar\/home<\/td>\n<\/tr>\n<tr class=\"row-5 odd\">\n\t<td class=\"column-1\">25 Mar 2026<\/td><td class=\"column-2\">Xiao-Wu Chen   (University of Science and Technology of China, Hefei, China)   <\/td><td class=\"column-3\"><\/td><td class=\"column-4\">Frobenius quotients, inflation categories and weighted projective lines<br \/>\n<br \/>\nAbstract. By the work of Kussin,  Lenzing  and Meltzer,  the category of vector bundles on a certain weighted projective line is closely related to the graded submodule problem, studied by Ringel-Schmidmeier. However, the connection is quite mysterious. We construct an explicit functor, which yields Kussin-Lenzing-Meltzer\u2019s stable equivalence. Inspired by Demonet-Iyama's work, we introduce a general notion of Frobenius quotients. We use multifold matrix factorizations in the proof. This is joint with Qiang Dong and Shiquan Ruan.<\/td><td class=\"column-5\">Wednesday 2pm\u20133pm<br \/>\nTime Zone Berlin, Rome, Paris<\/td><td class=\"column-6\">Register here to obtain the Zoom link:<br \/>\nhttps:\/\/sites.google.com\/view\/lagoonwebinar\/home<\/td>\n<\/tr>\n<tr class=\"row-6 even\">\n\t<td class=\"column-1\"><\/td><td class=\"column-2\"><\/td><td class=\"column-3\"><\/td><td class=\"column-4\"><\/td><td class=\"column-5\"><\/td><td class=\"column-6\"><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<!-- #tablepress-15 from cache -->\n\n\n","protected":false},"excerpt":{"rendered":"<p>Seminare und Vortr\u00e4ge im WS 2025\/2026<\/p>\n","protected":false},"author":2,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":[],"_links":{"self":[{"href":"https:\/\/www.mi.uni-koeln.de\/RepTheory\/wp-json\/wp\/v2\/pages\/18"}],"collection":[{"href":"https:\/\/www.mi.uni-koeln.de\/RepTheory\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.mi.uni-koeln.de\/RepTheory\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.mi.uni-koeln.de\/RepTheory\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.mi.uni-koeln.de\/RepTheory\/wp-json\/wp\/v2\/comments?post=18"}],"version-history":[{"count":25,"href":"https:\/\/www.mi.uni-koeln.de\/RepTheory\/wp-json\/wp\/v2\/pages\/18\/revisions"}],"predecessor-version":[{"id":1351,"href":"https:\/\/www.mi.uni-koeln.de\/RepTheory\/wp-json\/wp\/v2\/pages\/18\/revisions\/1351"}],"wp:attachment":[{"href":"https:\/\/www.mi.uni-koeln.de\/RepTheory\/wp-json\/wp\/v2\/media?parent=18"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}