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SUMMARY:João Faria Martins (University of Leeds)
DTSTART:20201030T170000Z
DTEND:20201030T180000Z
DTSTAMP:20260423T024650Z
UID:TQFT/18
DESCRIPTION:Title: <a href="https://researchseminars.org/talk/TQFT/18/">Cr
 ossed modules\, homotopy 2-types\, knotted surfaces and welded knots</a>\n
 by João Faria Martins (University of Leeds) as part of Topological Quantu
 m Field Theory Club (IST\, Lisbon)\n\n\nAbstract\nI will review the constr
 uction of invariants of knots\, loop braids and knotted surfaces derived f
 rom finite crossed modules. I will also show a method to calculate the alg
 ebraic homotopy 2-type of the complement of a knotted surface $\\Sigma$ em
 bedded in the 4-sphere from a movie presentation of $\\Sigma$. This will e
 ntail a categorified form of the Wirtinger relations for a knot group. Alo
 ng the way I will also show applications to welded knots in terms of a biq
 uandle related to the homotopy 2-type of the complement of the tube of a w
 elded knots.\n\nThe last stages of this talk are part of the framework of 
 the Leverhulme Trust research project grant:  RPG-2018-029: “Emergent Ph
 ysics From Lattice Models of Higher Gauge Theory.\n
LOCATION:https://researchseminars.org/talk/TQFT/18/
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