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In this paper, we compare several functors which take simplicial categories or model categories to complete Segal spaces, which are particularly nice simplicial spaces which, like simplicial categories, can be considered to be models for…

Algebraic Topology · Mathematics 2007-10-11 Julia E. Bergner

We answer the question to what extent homotopy (co)limits in categories with weak equivalences allow for a Fubini-type interchange law. The main obstacle is that we do not assume our categories with weak equivalences to come equipped with a…

Algebraic Topology · Mathematics 2017-11-07 Kay Werndli

Bialgebroids, separable bialgebroids, and weak Hopf algebras are compared from a categorical point of view. Then properties of weak Hopf algebras and their applications to finite index and finite depth inclusions of von Neumann algebras are…

Quantum Algebra · Mathematics 2007-05-23 K. Szlachanyi

It is shown that any finite-dimensional homomorphic image of an inverse limit of nilpotent not-necessarily-associative algebras over a field is nilpotent. More generally, this is true of algebras over a general commutative ring k, with…

Rings and Algebras · Mathematics 2021-10-15 George M. Bergman

Let p be a fibration over a finite simplicial complex, whose fibers have the homotopy type of finite simplicial complexes. Then p is equivalent to an approximate fibration whose total space is a compact ENR. The proof uses homotopy coherent…

Algebraic Topology · Mathematics 2011-09-29 Wolfgang Steimle

A hom-associative algebra is an algebra whose associativity is twisted by an algebra homomorphism. We show that the Hochschild type cochain complex of a hom-associative algebra carries a homotopy G-algebra structure. As a consequence, we…

Rings and Algebras · Mathematics 2018-11-09 Apurba Das

We classify the homotopy types of reduced 2-nilpotent simplicial groups in terms of the homology an d boundary invariants $b,\beta$. This contains as special cases results of J.H.C. Whitehead on 1-connected 4-dimensional complexes and of…

K-Theory and Homology · Mathematics 2010-09-01 Hans-Joachim Baues , Roman Mikhailov

We prove that a nilpotent space is both formal and coformal if and only if it is rationally homotopy equivalent to the derived spatial realization of a graded commutative Koszul algebra. We call such spaces Koszul spaces and we show that…

Algebraic Topology · Mathematics 2011-07-05 Alexander Berglund

In this paper we propose an approach to homotopical algebra where the basic ingredient is a category with two classes of distinguished morphisms: strong and weak equivalences. These data determine the cofibrant objects by an extension…

Algebraic Topology · Mathematics 2008-09-18 F. Guillen Santos , V. Navarro , P. Pascual , Agusti Roig

We show that almost nonnegatively curved m-dimensional manifolds are, up to finite cover, nilpotent spaces in the sense of homotopy theory and have C(m)-nilpotent fundamental groups. We also show that up to a finite cover almost…

Differential Geometry · Mathematics 2019-05-21 Vitali Kapovitch , Anton Petrunin , Wilderich Tuschmann

Category of pro-nilpotently extended differential graded commutative algebras is introduced. Chevalley-Eilenberg construction provides an equivalence between its certain full subcategory and the opposite to the full subcategory of strong…

Algebraic Topology · Mathematics 2024-06-18 Damjan Pištalo

In this paper, we study simplicial commutative algebras with finite Andr\'e-Quillen homology. Here we restrict our focus to simplicial algebras having characteristic 2. Our aim is to find a generalization of results established by the…

Commutative Algebra · Mathematics 2007-05-23 James M Turner

I show that simple finite vertex algebras are commutative, and that the Lie conformal algebra structure underlying a reduced (i.e., without nilpotent elements) finite vertex algebra is nilpotent.

Quantum Algebra · Mathematics 2012-10-19 Alessandro D'Andrea

In this article, we show that there is no cofibration category structure on the category of finite graphs with $\times$-homotopy equivalences as the class of weak equivalences. Further, we show that it is not possible to enlarge the class…

Algebraic Topology · Mathematics 2023-11-29 Shuchita Goyal , Rekha Santhanam

We discuss various concepts of $\infty$-homotopies, as well as the relations between them (focussing on the Leibniz type). In particular $\infty$-$n$-homotopies appear as the $n$-simplices of the nerve of a complete Lie ${\infty}$-algebra.…

Quantum Algebra · Mathematics 2013-09-09 David Khudaverdyan , Norbert Poncin , Jian Qiu

By careful analysis of the comparison map from a simplicial set to its image under Kan's ex-infinity functor we obtain a new and combinatorial proof that it is a weak homotopy equivalence. Moreover, we obtain a presentation of it as a…

Category Theory · Mathematics 2020-02-14 Sean Moss

The homotopy category of a model structure on a weakly idempotent complete additive category is proved to be equivalent to the additive quotient of the category of cofibrant-fibrant objects with respect to the subcategory of…

Representation Theory · Mathematics 2025-01-28 Xue-Song Lu , Pu Zhang

We describe a procedure to attach a nilpotent strong homotopy Lie algebra to every simple hypergraph and prove that two hypergraphs are isomorphic if and only if the corresponding strong homotopy Lie algebras are isomorphic. As an…

Combinatorics · Mathematics 2024-02-23 Marco Aldi , Samuel Bevins

This note extends Quillen's Theorem A to a large class of categories internal to topological spaces. This allows us to show that under a mild condition a fully faithful and essentially surjective functor between such topological categories…

Algebraic Topology · Mathematics 2024-06-12 David Michael Roberts

This paper provides an extensive study of the homotopy theory of types of algebras with units, like unital associative algebras or unital commutative algebras for instance. To this purpose, we endow the Koszul dual category of curved…

Algebraic Topology · Mathematics 2019-05-29 Brice Le Grignou