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Related papers: On pseudofunctors sending groups to 2-groups

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We develop a 2-dimensional version of accessibility and presentability compatible with the formalism of flat pseudofunctors. First we give prerequisites on the different notions of 2-dimensional colimits, filteredness and cofinality; in…

Category Theory · Mathematics 2025-08-05 Ivan Di Liberti , Axel Osmond

We define a 2-category structure (Pre-Orb) on the category of reduced complex orbifold atlases. We construct a 2-functor F from (Pre-Orb) to the 2-category (Grp) of proper \'etale effective groupoid objects over the complex manifolds. Both…

Algebraic Topology · Mathematics 2010-10-05 Matteo Tommasini

We introduce fibred type-theoretic fibration categories which are fibred categories between categorical models of Martin-L\"{o}f type theory. Fibred type-theoretic fibration categories give a categorical description of logical predicates…

Category Theory · Mathematics 2017-09-25 Taichi Uemura

We study unitary pseudonatural transformations (UPTs) between fibre functors Rep(G) -> Hilb, where G is a compact quantum group. For fibre functors F_1, F_2 we show that the category of UPTs F_1 -> F_2 and modifications is isomorphic to the…

Quantum Algebra · Mathematics 2022-01-13 Dominic Verdon

In this article, we consider a formulation of biset functors using the 2-category of finite sets with variable finite group actions. We introduce a 2-category $\mathbb{S}$, on which a biset functor can be regarded as a special kind of…

Category Theory · Mathematics 2015-12-08 Hiroyuki Nakaoka

We consider several types of non-existence theorems for functors. For example, there are no nontrivial functors from the category of groups (or the category of pointed sets, or vector spaces) to any small category. Another type of questions…

Category Theory · Mathematics 2025-05-20 Emmanuel Dror Farjoun , Sergei O. Ivanov , Aleksandr Krasilnikov , Anatolii Zaikovskii

This is mostly an overview. Given finitely presentable abelian categories $A$ and $B$, we sketch the construction of an abelian category of continuous functors from $A$ to $B$ that has nice $2$-categorical behaviour and gives an explicit…

Category Theory · Mathematics 2022-05-18 D. Kaledin

Given an operad $\mathcal{O}$, we define a notion of weak $\mathcal{O}$-monoids -- which we term $\mathcal{O}$-pseudomonoids -- in a 2-category. In the special case with the 2-category in question is the 2-category $\mathsf{Cat}$ of…

Category Theory · Mathematics 2024-04-02 Redi Haderi , Walker H. Stern

We associate to a bimonoidal functor, i.e. a bifunctor which is monoidal in each variable, a nonabelian version of a biextension. We show that such a biextension satisfies additional triviality conditions which make it a bilinear analog of…

Category Theory · Mathematics 2017-11-15 Ettore Aldrovandi

The notion of the center of an algebra over a field k has a far reaching generalization to algebras in monoidal categories. The center then lives in the monoidal center of the original category. This generalization plays an important role…

Quantum Algebra · Mathematics 2016-12-28 Alexei Davydov , Liang Kong , Ingo Runkel

Gluing of two pseudo functors has been studied by Deligne, Ayoub, and others in the construction of extraordinary direct image functors in \'etale cohomology, stable homotopy, and mixed motives of schemes. In this article, we study more…

Category Theory · Mathematics 2016-03-14 Weizhe Zheng

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

Simple optics are defined using actions of monoidal categories. Compound optics arise, for instance, as natural transformations between polynomial functors. Since a monoidal category is a special case of a bicategory, we formulate complex…

Category Theory · Mathematics 2022-03-24 Bartosz Milewski

In this work, we study the notion of cofinal functor of $\infty$-bicategories with respect to the theory of partially lax colimits. The main result of this paper is a characterization of cofinal functors of $\infty$-bicategories via…

Algebraic Topology · Mathematics 2023-04-17 Fernando Abellán , Walker H. Stern

We develop a general theory of (extended) inner autoequivalences of objects of any 2-category, generalizing the theory of isotropy groups to the 2-categorical setting. We show how dense subcategories let one compute isotropy in the presence…

Category Theory · Mathematics 2024-05-28 Pieter Hofstra , Martti Karvonen

In this article we analyze the structure of $2$-categories of symmetric projective bimodules over a finite dimensional algebra with respect to the action of a finite abelian group. We determine under which condition the resulting…

Representation Theory · Mathematics 2019-04-12 Volodymyr Mazorchuk , Vanessa Miemietz , Xiaoting Zhang

Let $C$ be an additive category with cokernels and let Mod($C$) be the category of additive functors from $C^{op}$ to the category Ab of abelian groups. Let mod($C$) be the full subcategory of Mod($C$) consisting of coherent functors. In…

Category Theory · Mathematics 2020-12-16 Mohammad Khazaei , Reza Sazeedeh

This thesis contains various results on unitary 2-representations of finite groups and their 2-characters, as well as on pivotal structures for fusion categories. The motivation is extended topological quantum field theory (TQFT), where the…

Quantum Algebra · Mathematics 2009-01-27 Bruce Bartlett

Abelian groups are classified by the existence of certain additive decompositions of group-valued functions of several variables with arity gap 2.

Combinatorics · Mathematics 2013-03-29 Miguel Couceiro , Erkko Lehtonen , Tamás Waldhauser

By regarding the classical non abelian cohomology of groups from a 2-dimensional categorical viewpoint, we are led to a non abelian cohomology of groupoids which continues to satisfy classification, interpretation and representation…

Category Theory · Mathematics 2007-05-23 V. Blanco , M. Bullejos , E. Faro