80 citations · 397 across the 30 of their papers we have counts for
6 papers · 1 filter
Lifting Problems and Transgression for Non-Abelian Gerbes
Thomas Nikolaus, Konrad Waldorf
We discuss various lifting and reduction problems for bundles and gerbes in the context of a strict Lie 2-group. We obtain a geometrical formulation (and a new proof) for the exact…
Bicategories in field theories - an invitation
Thomas Nikolaus, Christoph Schweigert
We explain some applications of bicategories in both classical and quantum field theory. This includes a modern perspective on some pioneering work of Max Kreuzer and Bert Schellek…
Strictification of weakly equivariant Hopf algebras
Jennifer Maier, Thomas Nikolaus, Christoph Schweigert
A weakly equivariant Hopf algebra is a Hopf algebra A with an action of a finite group G up to inner automorphisms. We show that each weakly equivariant Hopf algebra can be replace…
A Smooth Model for the String Group
Thomas Nikolaus, Christoph Sachse, Christoph Wockel
We construct a model for the string group as an infinite-dimensional Lie group. In a second step we extend this model by a contractible Lie group to a Lie 2-group model. To this en…
Four Equivalent Versions of Non-Abelian Gerbes
Thomas Nikolaus, Konrad Waldorf
We recall and partially improve four versions of smooth, non-abelian gerbes: Cech cocycles, classifying maps, bundle gerbes, and principal 2-bundles. We prove that all these four v…
Equivariant Modular Categories via Dijkgraaf-Witten Theory
Jennifer Maier, Thomas Nikolaus, Christoph Schweigert
Based on a weak action of a finite group J on a finite group G, we present a geometric construction of J-equivariant Dijkgraaf-Witten theory as an extended topological field theory…