Orbifolds by 2-groups and decomposition

Understand

In this paper we study three-dimensional orbifolds by 2-groups with a trivially-acting one-form symmetry group BK.

• These orbifolds have a global two-form symmetry, and so one expects that they decompose into (are equivalent to) a disjoint union of other three-dimensional theories, which we demonstrate.
• These theories can be interpreted as sigma models on 2-gerbes, whose formal structures reflect properties of the orbifold construction.