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The behaviour of limits of weak morphisms in 2-dimensional universal algebra is not 2-categorical in that, to fully express the behaviour that occurs, one needs to be able to quantify over strict morphisms amongst the weaker kinds.…

Category Theory · Mathematics 2022-01-31 John Bourke

We prove that a weak equivalence between cofibrant props induces a weak equivalence between the associated classifying spaces of algebras. This statement generalizes to the prop setting a homotopy invariance result which is well known in…

Algebraic Topology · Mathematics 2016-01-20 Sinan Yalin

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

Theorem (after Giraud, SGA 4): Suppose $A$ is a simplicial category. The following conditions are equivalent: (i) There is a cofibrantly generated closed model category $M$ such that $A$ is equivalent to the Dwyer-Kan simplicial…

Algebraic Topology · Mathematics 2007-05-23 Carlos Simpson

We study hyperbolic cohomology classes in the general context of simplicial complexes and prove homological invariance statements for them. We relate the existence of hyperbolic cohomology classes to the non-amenability of the fundamental…

Geometric Topology · Mathematics 2008-08-12 M. Brunnbauer , D. Kotschick

Essential $\aleph_0$-categoricity; i.e., $\aleph_0$-categoricity in some full countable language, is shown to be a robust notion for strongly minimal compact complex manifolds. Characterisations of triviality and essential…

Logic · Mathematics 2010-07-06 Rahim Moosa , Anand Pillay

This paper provides a solution to the open problen formulated in Glotko and Kuzminov article, as well as examples of non-strict universal epimorphisms and monomorphisms.

Category Theory · Mathematics 2026-03-16 Max Zinchenko

Given a symmetric monoidal $\infty$-category $\mathscr{E}$, compatible with finite colimits, we show that the functor sending a simplicial object in $\mathscr{E}$ to its skeletal filtration is canonically lax symmetric monoidal. This…

Algebraic Topology · Mathematics 2025-10-23 Liam Keenan , Maximilien Péroux

Lenses are a well-established structure for modelling bidirectional transformations, such as the interactions between a database and a view of it. Lenses may be symmetric or asymmetric, and may be composed, forming the morphisms of a…

Machine Learning · Computer Science 2019-05-03 Brendan Fong , Michael Johnson

For a category B with finite products, we first characterize pseudofunctors from B to Cat whose corresponding opfibration is cartesian monoidal. Among those, we then characterize the ones which extend to pseudofunctors from internal groups…

Category Theory · Mathematics 2022-06-03 Alan S. Cigoli , Sandra Mantovani , Giuseppe Metere

We give an alternative presentation of braided monoidal categories. Instead of the usual associativity and braiding we have just one constraint (the b-structure). In the unital case, the coherence conditions for a b-structure are shown to…

Category Theory · Mathematics 2013-07-24 Alexei Davydov , Ingo Runkel

We construct a model category structure on the category of diffeological spaces which is Quillen equivalent to the model structure on the category of topological spaces based on the notions of Serre fibrations and weak homotopy…

Algebraic Topology · Mathematics 2018-10-10 Tadayuki Haraguchi , Kazuhisa Shimakawa

Given a locally presentable category together with a suitable functorial cylinder object, we construct model structures which are sensitive to the `direction' of the cylinder. We show that the Covariant and Contravariant model structures on…

Category Theory · Mathematics 2019-08-20 Hoang Kim Nguyen

For a complete and cocomplete category $\mathcal{C}$ with a well-behaved class of `projectives' $\bar{\mathcal{P}}$, we construct a model structure on the category $s\mathcal{C}$ of simplicial objects in $\mathcal{C}$ where the weak…

Category Theory · Mathematics 2018-03-07 Ged Corob Cook

We prove that categories enriched in the Thomason model structure admit a model structure that is Quillen equivalent to the Bergner model structure on simplicial categories, providing a new model for (infinity,1)-categories. Along the way,…

Algebraic Topology · Mathematics 2023-11-20 Dmitri Pavlov

We construct a left semi-model category of "marked strict $\infty$-categories" for which the fibrant objects are those whose marked arrows satisfy natural closure properties and are weakly invertible. The canonical model structure on strict…

Category Theory · Mathematics 2025-03-26 Simon Henry Felix Loubaton

We adapt the classical framework of algebraic theories to work in the setting of (infinity,1)-categories developed by Joyal and Lurie. This gives a suitable approach for describing highly structured objects from homotopy theory. A central…

Algebraic Topology · Mathematics 2010-11-16 James Cranch

In this paper, we introduce a new category of simplicial effects that extends the categories of effect algebras and their multi-object counterpart, effect algebroids. Our approach is based on relaxing the associativity condition satisfied…

Category Theory · Mathematics 2025-02-11 Cihan Okay , Victor Castillo , Walker H. Stern

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

In this paper, we provide a notion of $\infty$-bicategories fibred in $\infty$-bicategories which we call 2-Cartesian fibrations. Our definition is formulated using the language of marked biscaled simplicial sets: Those are scaled…

Algebraic Topology · Mathematics 2021-06-08 Fernando Abellán García , Walker H. Stern
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