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We introduce the notion of a "category with path objects", as a slight strengthening of Kenneth Brown's classic notion of a "category of fibrant objects". We develop the basic properties of such a category and its associated homotopy…

Category Theory · Mathematics 2017-06-21 Benno van den Berg , Ieke Moerdijk

We continue the program of structural differential geometry that begins with the notion of a tangent category, an axiomatization of structural aspects of the tangent functor on the category of smooth manifolds. In classical geometry, having…

Category Theory · Mathematics 2019-05-01 R. F. Blute , G. S. H. Cruttwell , R. B. B. Lucyshyn-Wright

Suppose that $\mathcal{A}$ is an abelian category whose derived category $\mathcal{D}(\mathcal{A})$ has $Hom$ sets and arbitrary (small) coproducts, let $T$ be a (not necessarily classical) ($n$-)tilting object of $\mathcal{A}$ and let…

Representation Theory · Mathematics 2016-07-08 Luisa Fiorot , Francesco Mattiello , Manuel Saorín

We introduce a notion of globular multicategory with homomorphism types. These structures arise when organizing collections of "higher category-like" objects such as type theories with identity types. We show how these globular…

Category Theory · Mathematics 2020-05-29 Christopher J. Dean

Some basic features of the simultaneous inclusion of discrete fibrations and discrete opfibrations on a category A in the category of categories over A are studied; in particular, the reflections and the coreflections of the latter in the…

Category Theory · Mathematics 2007-05-23 Claudio Pisani

This paper is devoted to further results on the nontrivially associated categories $\mathcal{C}$ and $\mathcal{D}$, which are constructed from a choice of coset representatives for a subgroup of a finite group. We look at the construction…

Quantum Algebra · Mathematics 2007-05-23 M. M. Al-Shomrani , E. J. Beggs

By proving that, if the quotient space S(X) of the connected components of the locally compact metric space (X,d) is compact, then the full group I(X,d) of isometries of X is closed in C(X,X) with respect to the pointwise topology, i.e.,…

General Topology · Mathematics 2007-05-23 Antonios Manoussos , Polychronis Strantzalos

This note is about the smash product of pointed topological spaces, without relying on some convenient subcategory. We deal with its partial associativity properties and their connection with the function spaces, introducing a property of…

Algebraic Topology · Mathematics 2024-09-04 Marco Grandis

We explore an alternative definition of unit in a monoidal category originally due to Saavedra: a Saavedra unit is a cancellative idempotent (in a 1-categorical sense). This notion is more economical than the usual notion in terms of…

Category Theory · Mathematics 2010-03-09 Joachim Kock

We define boundedness properties on the contractible fixed points set of the time-one map of an identity isotopy on a closed oriented surface with genus $g\geq1$. In symplectic geometry, a classical object is the notion of action function,…

Dynamical Systems · Mathematics 2012-09-11 Jian Wang

We systematically develop the theory of definable functors between compactly generated triangulated categories. Such functors preserve pure triangles, pure injective objects, and definable subcategories, and as such appear in a wide range…

Category Theory · Mathematics 2025-03-03 Isaac Bird , Jordan Williamson

For a rigid object $M$ in an algebraic triangulated category $\mathcal{T}$, a functor pr$(M)\to\mathcal{H}^{[-1,0]}({\rm proj}\, A)$ is constructed, which essentially takes an object to its `presentation', where pr$(M)$ is the full…

Representation Theory · Mathematics 2025-09-11 Dong Yang

We show that given a rigid C*-tensor category, there is an equivalence of categories between normalized irreducible Q-systems, also known as connected unitary Frobenius algebra objects, and compact connected W*-algebra objects. Although…

Operator Algebras · Mathematics 2017-07-10 Corey Jones , David Penneys

Many Properties of a category X, as for instance the existence of an adjoint or a factorization system, are a consequence of the cowellpoweredness of X. In the absence of cowellpoweredness, for general results, fairly strong assumption on…

Category Theory · Mathematics 2007-05-23 Vishvajit V. S. Gautam

In this paper, we study the compactness of the product and the commutator of two inner projections on the Hardy spaces over the unit disk and the polydisc. For the single-variable case, we provide a complete characterization of the…

Functional Analysis · Mathematics 2026-04-28 Peiran Zhang , Roumei Tian , Yufeng Lu , Yixin Yang , Chao Zu

Over an associative ring we consider a class $\mathbb{X}$ of left modules which is closed under set-indexed coproducts and direct summands. We investigate when the triangulated homotopy category $\mathsf{K}(\mathbb{X})$ is compactly…

Commutative Algebra · Mathematics 2007-05-23 Henrik Holm , Peter Jørgensen

We introduce some deformations of the biset category and prove a semisimplicity property. We also consider another group category, called the subgroup category, whose morphisms are subgroups of direct products, the composition being star…

Representation Theory · Mathematics 2020-01-09 Laurence Barker , İsmail Alperen Öğüt

In a previous work we proved the uniqueness and functoriality of primary unfoldings on simple Thom-Mather spaces, which is a functor to the category of smooth manifolds. In this article we extend these results for any stratified Thom-Mather…

Algebraic Topology · Mathematics 2010-04-29 T. Guardia , G. Padilla

We introduce the compactness locus of a geometric functor between rigidly-compactly generated tensor-triangulated categories, and describe it for several examples arising in equivariant homotopy theory and algebraic geometry. It is a subset…

Category Theory · Mathematics 2019-01-29 Beren Sanders

Given a symmetric monoidal category $C$ with product $\sqcup$, where the neutral element for the product is an initial object, we consider the poset of $\sqcup$-complemented subobjects of a given object $X$. When this poset has finite…

Combinatorics · Mathematics 2025-07-30 Kevin Ivan Piterman , Volkmar Welker