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We study tensor structures on (Rep G)-module categories defined by actions of a compact quantum group G on unital C*-algebras. We show that having a tensor product which defines the module structure is equivalent to enriching the action of…

Operator Algebras · Mathematics 2021-07-01 Sergey Neshveyev , Makoto Yamashita

In this thesis we study two main topics which culminate in a proof that four distinct definitions of the equivariant derived category of a smooth algebraic group $G$ acting on a variety $X$ are in fact equivalent. In the first part of this…

Algebraic Geometry · Mathematics 2023-02-01 Geoff Vooys

We define equivariantization of tensor categories under tensor group scheme actions and give necessary and sufficient conditions for an exact sequence of tensor categories to be an equivariantization under a finite group or finite group…

Quantum Algebra · Mathematics 2011-12-15 Alain Bruguières , Sonia Natale

Let $G$ be a finite group acting on an ice quiver with potential $(Q, F, W)$. We construct the corresponding $G$-equivariant relative cluster category and $G$-equivariant Higgs category, extending the work of Demonet. Using the orbit…

Representation Theory · Mathematics 2026-05-12 Yilin Wu

The bicategorical point of view provides a natural setting for many concepts in the representation theory of monoidal categories. We show that centers of twisted bimodule categories correspond to categories of 2-dimensional natural…

Category Theory · Mathematics 2023-06-09 Bojana Femić , Sebastian Halbig

We consider the 3-category $2\mathfrak{C}at$ whose objects are 2-categories, 1-morphisms are lax functors, 2-morphisms are lax transformations and 3-morphisms are modifications. The aim is to show that it carries interesting…

Representation Theory · Mathematics 2025-08-11 Fei Xu , Maoyin Zhang

We prove that the adjoint equivariant derived category of a reductive group $G$ is equivalent to the appropriately defined monoidal center of the torus-equivariant version of the Hecke category. We use this to give new proofs, independent…

Representation Theory · Mathematics 2024-06-13 Roman Bezrukavnikov , Andrei Ionov , Kostiantyn Tolmachov , Yakov Varshavsky

A finite tensor category is called pointed if all its simple objects are invertible. We find necessary and sufficient conditions for two pointed semisimple categories to be dual to each other with respect to a module category. Whenever the…

Quantum Algebra · Mathematics 2009-12-19 Deepak Naidu

Imprimitivity theorems provide a fundamental tool for studying the representation theory and structure of crossed-product C*-algebras. In this work, we show that the Imprimitivity Theorem for induced algebras, Green's Imprimitivity Theorem…

Operator Algebras · Mathematics 2007-05-23 Siegfried Echterhoff , S. Kaliszewski , John Quigg , Iain Raeburn

We give a definition of an operad with general groups of equivariance suitable for use in any symmetric monoidal category with appropriate colimits. We then apply this notion to study the 2-category of algebras over an operad in Cat. We…

Category Theory · Mathematics 2014-02-28 Alexander S. Corner , Nick Gurski

We study group action on bimodules and bimodule categories and prove for them analogues of the results known for representations of skew group algebras, mainly in the case, when the action is separable.

Representation Theory · Mathematics 2016-03-02 Yuriy A. Drozd

Motivated by the relation between the Drinfeld double and central property (T) for quantum groups, given a rigid C*-tensor category C and a unitary half-braiding on an ind-object, we construct a *-representation of the fusion algebra of C.…

Operator Algebras · Mathematics 2021-06-10 Sergey Neshveyev , Makoto Yamashita

We present a comparative study of certain invariants defined for group actions and their analogues defined for orbifolds. In particular, we prove that Fadell's equivariant category for $G$-spaces coincides with the Lusternik-Schnirelmann…

Algebraic Topology · Mathematics 2022-08-30 Andres Angel , Hellen Colman

We establish a set of general results to study how the Galois action on modular tensor categories interacts with fusion subcategories. This includes a characterization of fusion subcategories of modular tensor categories which are closed…

Quantum Algebra · Mathematics 2021-11-10 Julia Plavnik , Andrew Schopieray , Zhiqiang Yu , Qing Zhang

We prove that the Drinfeld center of a fusion 2-category is invariant under Morita equivalence. We go on to show that the concept of Morita equivalence between connected fusion 2-categories recovers exactly the notion of Witt equivalence…

Quantum Algebra · Mathematics 2025-06-18 Thibault D. Décoppet

We prove that for a large class of well-behaved cocomplete categories $\mathcal C$ the weak and strong Drinfeld centers of the monoidal category $\mathcal{E}$ of cocontinuous endofunctors of $\mathcal{C}$ coincide. This generalizes similar…

Category Theory · Mathematics 2022-03-02 Alexandru Chirvasitu

A Lie 2-group $G$ is a category internal to the category of Lie groups. Consequently it is a monoidal category and a Lie groupoid. The Lie groupoid structure on $G$ gives rise to the Lie 2-algebra $\mathbb{X}(G)$ of multiplicative vector…

Differential Geometry · Mathematics 2019-08-29 Eugene Lerman

Let $(\mathcal{C}, \otimes)$ be a monoidal dg-category. We construct a complex controlling the deformation of the monoidal structure on $\mathcal{C}$ together with the deformation of the underlying dg-category itself. We show that in the…

Algebraic Geometry · Mathematics 2026-04-08 Slava Pimenov , Angel Toledo

We prove that given any compact group G, there exists a minimal action of G on a II_1 factor M such that the bimodule category of the fixed-point II_1 factor M^G is naturally equivalent with the representation category of G. In particular,…

Operator Algebras · Mathematics 2010-07-05 Sébastien Falguières , Stefaan Vaes

We develop the Morita theory of fusion 2-categories. In order to do so, we begin by proving that the relative tensor product of modules over a separable algebra in a fusion 2-category exists. We use this result to construct the Morita…

Category Theory · Mathematics 2023-06-06 Thibault D. Décoppet