BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Kürsat Sözer (Université de Lille) DTSTART:20260422T090000Z DTEND:20260422T100000Z DTSTAMP:20260423T034446Z UID:EQuAL/55 DESCRIPTION:Title: Q uantum invariants of maps from 3-manifolds to homotopy 2-types\nby Kü rsat Sözer (Université de Lille) as part of European Quantum Algebra Lec tures (EQuAL)\n\n\nAbstract\nTopological quantum field theories (TQFTs) pr ovide a powerful framework for constructing invariants of manifolds. Their extension to homotopy quantum field theories (HQFTs) refines these invari ants by incorporating maps to a target space. In this talk\, I recall Dijk graaf–Witten invariants and their state-sum description\, and explain th eir extension to HQFTs with target BG. I then discuss the passage from gro ups to crossed modules as algebraic models for homotopy 2-types\, and outl ine the associated tensor-categorical and Hopf-algebraic structures\, incl uding Hopf crossed module coalgebras. Finally\, I present joint work with Alexis Virelizier\, where we construct Kuperberg-type invariants for pairs (M\,g)\, with g∈[M\,B\\chi] where \\chi is a crossed module. The constr uction uses \\chi-labeled Heegaard diagrams and involutory Hopf \\chi-coal gebras\, extending the classical Kuperberg invariant and admitting an inte rpretation in terms of invariant of flat principal 2-bundles.\n LOCATION:https://researchseminars.org/talk/EQuAL/55/ END:VEVENT END:VCALENDAR