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An equivalent description of a symmetric monoidal category is introduced in which, instead of separate associator and commutator isomorphisms satisfying the usual coherence axioms, we simply have associo-commutator isomorphisms satisfying…

Category Theory · Mathematics 2025-12-25 Josep Elgueta

The most natural notion of a simplicial nerve for a (weak) bicategory was given by Duskin, who showed that a simplicial set is isomorphic to the nerve of a $(2,1)$-category (i.e. a bicategory with invertible $2$-morphisms) if and only if it…

Category Theory · Mathematics 2014-01-31 Nathaniel Watson

For a small category $\mathcal{D}$ we define fibrations of simplicial presheaves on the category $\mathcal{D}\times\Delta$, which we call localized $\mathcal{D}$-left fibration. We show these fibrations can be seen as fibrant objects in a…

Category Theory · Mathematics 2021-08-16 Nima Rasekh

We give a simple and more elementary proof that the notions of Domain of Holomorphy and Weak Domain of Holomorphy are equivalent. This proof is based on a combination of Baire's Category Theorem and Montel's Theorem. We also obtain…

Complex Variables · Mathematics 2017-05-30 V. Nestoridis

We apply the Acyclicity Theorem of Hess, Kerdziorek, Riehl, and Shipley (recently corrected by Garner, Kedziorek, and Riehl) to establishing the existence of model category structure on categories of coalgebras over comonads arising from…

Algebraic Topology · Mathematics 2018-08-15 Kathryn Hess , Magdalena Kedziorek

Every smooth manifold contains particles which propagate. These form objects and morphisms of a category equipped with a functor to the category of Abelian groups, turning this into a 0+1 topological field theory. We investigate the…

Symplectic Geometry · Mathematics 2009-06-26 Jean-Yves Welschinger

The basic notions of category theory, such as limit, adjunction, and orthogonality, all involve assertions of the existence and uniqueness of certain arrows. Weak notions arise when one drops the uniqueness requirement and asks only for…

Category Theory · Mathematics 2012-05-25 Stephen Lack , Jiri Rosicky

A well-known, but often ignored issue in Yoneda-style definitions of cohomology objects via collections of $n$-step extensions (i.e., equivalence classes of exact sequences of a given length $n$ between two given objects, usually subject to…

Category Theory · Mathematics 2025-08-19 Sébastien Mattenet , Tim Van der Linden , Raphaël M. Jungers

In this short note, we will show the following weak evidence of S. Lang conjecture over function fields. Let f : X ---> Y be a projective and surjective morphism of algebraic varieties over an algebraically closed field k of characteristic…

alg-geom · Mathematics 2008-02-03 Atsushi Moriwaki

We prove the existence of Morita model structures on the categories of small simplicial categories, simplicial sets, simplicial operads and dendroidal sets, modelling the Morita homotopy theory of $(\infty,1)$-categories and…

Algebraic Topology · Mathematics 2019-09-04 Giovanni Caviglia , Javier J. Gutiérrez

An unrepresentable cohomological functor of finite type of the bounded derived category of coherent sheaves of a compact complex manifold of dimension greater than one with no proper closed subvariety is given explicitly in categorical…

Algebraic Geometry · Mathematics 2015-05-18 Keiji Oguiso

The main purpose of this paper is to introduce the structure of soft group category. In this category, we determine some special objects and morphisms having a universal structure such as the final object and product. Therefore, the…

Algebraic Topology · Mathematics 2023-08-01 Nazmiye Alemdar , Hasan Arslan

In this paper, we consider the model structure on the category of cellular sets originally conjectured by Cisinski and Joyal to give a model for the homotopy theory of weak (\omega)-categories. We demonstrate first that any…

Category Theory · Mathematics 2012-09-11 Harry Gindi

We introduce the dendroidal analogs of the notions of complete Segal space and of Segal category, and construct two appropriate model categories for which each of these notions corresponds to the property of being fibrant. We prove that…

Category Theory · Mathematics 2013-03-26 Denis-Charles Cisinski , Ieke Moerdijk

We extend the homotopy theories based on point reduction for finite spaces and simplicial complexes to finite acyclic categories and $\Delta$-complexes, respectively. The functors of classifying spaces and face posets are compatible with…

Algebraic Topology · Mathematics 2017-07-06 Kohei Tanaka

We discuss a variant of the category of dendroidal sets, the so-called closed dendroidal sets which are indexed by trees without leaves. This category carries a Quillen model structure which behaves better than the one on general dendroidal…

Algebraic Topology · Mathematics 2018-11-15 Ieke Moerdijk

We describe a finitary 2-monad on a locally finitely presentable 2-category for which not every pseudoalgebra is equivalent to a strict one. This shows that having rank is not a sufficient condition on a 2-monad for every pseudoalgebra to…

Category Theory · Mathematics 2011-01-12 Michael A. Shulman

In this paper we prove that a morphism between schemes or stacks naturally corresponds to a symmetric monoidal functor between stable infinity-categories of quasi-coherent complexes. It can be viewed as a derived analogue of Tannaka…

Algebraic Geometry · Mathematics 2012-09-28 Hiroshi Fukuyama , Isamu Iwanari

A monoidal model category is a model category with a compatible closed monoidal structure. Such things abound in nature; simplicial sets and chain complexes of abelian groups are examples. Given a monoidal model category, one can consider…

Algebraic Topology · Mathematics 2007-05-23 Mark Hovey

We define the geometric simpleness for toroidal groups. We give an example of quasi-abelian variety which is geometrically simple, but not simple. We show that any quasi-abelian variety is isogenous to a product of geometrically simple…

Complex Variables · Mathematics 2018-09-24 Yukitaka Abe