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Related papers: A Note on "Extensional PERs"

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Motivated by the analysis and geometry of metric-measure structures in infinite dimensions, we study the category of extended metric-topological spaces, along with many of its distinguished subcategories (such as the one of compact spaces).…

Category Theory · Mathematics 2026-01-13 Enrico Pasqualetto , Timo Schultz , Janne Taipalus

A new construction to associate an internal category to an enriched one is presented. The key concept is that of extensive ambient category, and the construction follows the one that associates a category whose idempotents split to a given…

Category Theory · Mathematics 2022-08-03 Matteo Di Domenico

A coextensive category can be defined as a category $\mathcal{C}$ with finite products such that for each pair $X,Y$ of objects in $\mathcal{C}$, the canonical functor $\times\colon X/\mathcal{C} \times Y/\mathcal{C} \to (X \times…

Category Theory · Mathematics 2021-04-27 David Neal Broodryk

We generalize the construction of tensor categories of endomorphisms of a type III factor $M$ associated with a $G$-kernel, from the case of a discrete group $G$ to that of a compact second countable group. Our approach is based on the…

Operator Algebras · Mathematics 2026-05-19 Marcel Bischoff , Pradyut Karmakar

We introduce an enriched notion of a coalgebra over an operad P in a symmetric monoidal V-category C. When C is semicartesian and P is unital, we construct a V-endofunctor on C associated to P and give conditions under which it is a…

Category Theory · Mathematics 2026-05-04 Oisín Flynn-Connolly

We show that the endomorphisms of a compact connected group that extend to endomorphisms of every compact overgroup are precisely the trivial one and the inner automorphisms; this is an analogue, for compact connected groups, of results due…

Group Theory · Mathematics 2023-09-26 Alexandru Chirvasitu

Some basic features of the simultaneous inclusion of discrete fibrations and discrete opfibrations in categories over a base category X are considered. In particular, we illustrate the formulas (|P)x = ten(x/X,P) ; (P|)x = hom(X/x,P) which…

Category Theory · Mathematics 2007-05-23 Claudio Pisani

Suppose $(\mathcal{C},\mathbb{E},\mathfrak{s})$ is an $n$-exangulated category. We show that the idempotent completion and the weak idempotent completion of $\mathcal{C}$ are again $n$-exangulated categories. Furthermore, we also show that…

Category Theory · Mathematics 2024-08-23 Carlo Klapproth , Dixy Msapato , Amit Shah

Graduated locally finitely presentable categories are introduced, examples include categories of sets, vector spaces, posets, presheaves and Boolean algebras. A finitary functor between graduated locally finitely presentable categories is…

Category Theory · Mathematics 2024-02-06 Jirí Adámek , Lurdes Sousa

We derive faithful inclusions of C*-algebras from a coend-type construction in unitary tensor categories. This gives rise to different potential notions of discreteness for an inclusion in the non-irreducible case, and provides a unified…

Operator Algebras · Mathematics 2026-01-06 Lucas Hataishi , Roberto Hernández Palomares

A coextensive category can be defined as a category $\mathcal{C}$ with finite products such that for each pair $X,Y$ of objects in $\mathcal{C}$, the canonical functor $\times\colon X/\mathcal{C} \times Y/\mathcal{C} \to (X \times…

Category Theory · Mathematics 2020-08-11 David Neal Broodryk

We identify the complex plane C with the open unit disc D={z:|z|<1} by the homeomorphism z --> z/(1+|z|). This leads to a compactification $\bar{C}$ of C, homeomorphic to the closed unit disc. The Euclidean metric on the closed unit disc…

Complex Variables · Mathematics 2016-11-18 V. Nestoridis , N. Papadatos

We extend to singular cardinals the model-theoretical relation $\lambda \stackrel{\kappa}{\Rightarrow} \mu$ introduced in P. Lipparini, The compactness spectrum of abstract logics, large cardinals and combinatorial principles, Boll. Unione…

Logic · Mathematics 2008-05-13 Paolo Lipparini

If $\mathcal P$ is a family of filters over some set $I$, a topological space $X$ is \emph{sequencewise $\mathcal P$-\brfrt compact} if, for every $I$-indexed sequence of elements of $X$, there is $F \in \mathcal P$ such that the sequence…

General Topology · Mathematics 2016-08-30 Paolo Lipparini

The work is devoted to the extension groups in the category of functors from a small category to an additive category with an Abelian structure in the sense of Heller. It is constructed a spectral sequence which converges to the extension…

Category Theory · Mathematics 2009-09-28 A. A. Husainov , A. Pancar , M. Yapici

G. Conner and K. Eda (Topology and its Applications, 146, (2005), 317-328.) introduced a new construction of spaces from groups. They remarked that the construction is not categorical. In this paper, based on the work of Conner and Eda, we…

Algebraic Topology · Mathematics 2011-03-10 Hanieh Mirebrahimi , Behrooz Mashayekhy

We show that a compact rigid balanced braided monoidal category with enough compact projective objects gives rise to a system of mapping class group representations compatible with the gluing along marked intervals. A motivation to consider…

Quantum Algebra · Mathematics 2026-02-24 Deniz Yeral

Whereas formal category theory is classically considered within a $2$-category, in this paper a double-dimensional approach is taken. More precisely we develop such theory within the setting of augmented virtual double categories, a notion…

Category Theory · Mathematics 2022-10-11 Seerp Roald Koudenburg

For an additive category $\mathbf{P}$ we provide an explict construction of a category $\mathcal{Q}( \mathbf{P} )$ whose objects can be thought of as formally representing $\frac{\mathrm{im}( \gamma )}{\mathrm{im}( \rho ) \cap \mathrm{im}(…

Category Theory · Mathematics 2024-08-07 Sebastian Posur

The theory of ergodic optimization for distance-expanding maps is extended to Gauss's continued fraction map. Since the set of invariant probability measures is not weak$^*$ closed, we establish a characterisation of the closure of this…

Dynamical Systems · Mathematics 2025-12-29 Yinying Huang , Oliver Jenkinson , Zhiqiang Li