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Hypergraph categories have been rediscovered at least five times, under various names, including well-supported compact closed categories, dgs-monoidal categories, and dungeon categories. Perhaps the reason they keep being reinvented is…

Category Theory · Mathematics 2019-01-23 Brendan Fong , David I Spivak

For any finite totally ordered set, the multisets of intervals form an abelian category. Various classes of subcategories admit natural combinatorial descriptions, and counting them yields familiar integer sequences. Surprisingly, in some…

Representation Theory · Mathematics 2026-02-02 Henning Krause , Balduin Stoye

We introduce a new cubical model for homotopy types. More precisely, we'll define a category Qs with the following features: Qs is a PROP containing the classical box category as a subcategory, the category Qs-Set of presheaves of sets on…

Algebraic Topology · Mathematics 2009-10-27 Samuel B. Isaacson

We propose a graphical language that accommodates two monoidal structures: a multiplicative one for pairing and an additional one for branching. In this colored PROP, whether wires in parallel are linked through the multiplicative structure…

Logic in Computer Science · Computer Science 2025-12-29 Kostia Chardonnet , Marc de Visme , Benoît Valiron , Renaud Vilmart

We present a counterexample showing that Markov categories with conditionals (such as BorelStoch) need not validate a natural scheme of axioms which we call contraction identities. These identities hold in every traced monoidal category, so…

Category Theory · Mathematics 2025-09-26 Dario Stein , Márk Széles

In some bicategories, the 1-cells are `morphisms' between the 0-cells, such as functors between categories, but in others they are `objects' over the 0-cells, such as bimodules, spans, distributors, or parametrized spectra. Many…

Category Theory · Mathematics 2010-03-15 Michael A. Shulman

If $\mathbf{C}$ is a category with pullbacks then there is a bicategory with the same objects as $\mathbf{C}$, spans as morphisms, and maps of spans as 2-morphisms, as shown by Benabou. Fong has developed a theory of "decorated" cospans,…

Category Theory · Mathematics 2017-09-20 Kenny Courser

This paper introduces monoidal (super)categories resembling the Brauer category. For all categories, we can construct bases of the hom-spaces using Brauer diagrams. These categories include the Brauer category, its deformation the…

Representation Theory · Mathematics 2024-06-27 Sigiswald Barbier

We describe the multiplicative structures that arise on categories of equivariant modules over certain equivariant commutative ring spectra. Building on our previous work on N-infinity ring spectra, we construct categories of equivariant…

Algebraic Topology · Mathematics 2019-08-07 Andrew J. Blumberg , Michael A. Hill

We work with a generalization of knot theory, in which one diagram is reachable from another via a finite sequence of moves if a fixed condition, regarding the existence of certain morphisms in an associated category, is satisfied for every…

Geometric Topology · Mathematics 2019-10-29 Maciej Niebrzydowski

The concept of process is ubiquitous in science, engineering and everyday life. Category theory, and monoidal categories in particular, provide an abstract framework for modelling processes of many kinds. In this paper, we concentrate on…

Category Theory · Mathematics 2019-06-19 Valtteri Lahtinen , Antti Stenvall

Game comonads offer a categorical view of a number of model-comparison games central to model theory, such as pebble and Ehrenfeucht-Fra\"iss\'e games. Remarkably, the categories of coalgebras for these comonads capture preservation of…

Logic in Computer Science · Computer Science 2024-07-02 Samson Abramsky , Luca Reggio

Monoidal algebraic structures consist of operations that can have multiple outputs as well as multiple inputs, which have applications in many areas including categorical algebra, programming language semantics, representation theory,…

Logic in Computer Science · Computer Science 2015-10-14 Aleks Kissinger , Vladimir Zamdzhiev

Diagrammatic sets are presheaves on a rich category of shapes, whose definition is motivated by combinatorial topology and higher-dimensional diagram rewriting. These shapes include representatives of oriented simplices, cubes, and positive…

Algebraic Topology · Mathematics 2024-07-16 Clémence Chanavat , Amar Hadzihasanovic

We call a \emph{comb} a map $f:I\to [0,\infty)$, where $I$ is a compact interval, such that $\{f\ge \varepsilon\}$ is finite for any $\varepsilon$. A comb induces a (pseudo)-distance $\dtf$ on $\{f=0\}$ defined by $\dtf(s,t) =…

General Topology · Mathematics 2020-08-26 Amaury Lambert , Geronimo Uribe Bravo

We consider framed chord diagrams, i.e. chord diagrams with chords of two types. It is well known that chord diagrams modulo 4T-relations admit Hopf algebra structure, where the multiplication is given by any connected sum with respect to…

Geometric Topology · Mathematics 2015-07-01 Denis Ilyutko , Vassily Manturov

Arboreal categories were introduced as an axiomatic framework for game comonads, which provide a comonadic view on many model-comparison games in logic. We demonstrate the inadequacy of the axiom stating that paths are connected. We then…

Logic in Computer Science · Computer Science 2026-03-24 Tomáš Jakl , Luca Reggio

Wehrheim and Woodward have shown how to embed all the canonical relations between symplectic manifolds into a category in which the composition is the usual one when transversality and embedding assumptions are satisfied. A morphism in…

Symplectic Geometry · Mathematics 2011-03-14 Alan Weinstein

We adapt the notion of an algebraic theory to work in the setting of quasicategories developed recently by Joyal and Lurie. We develop the general theory at some length. We study one extended example in detail: the theory of commutative…

Algebraic Topology · Mathematics 2011-09-09 James Cranch

Dual comb spectroscopy allows for high-resolution spectra to be measured over broad bandwidths, but an essential requirement for coherent integration is the availability of a phase reference. Usually, this means that the combs' phase and…

Optics · Physics 2016-06-01 David Burghoff , Yang Yang , Qing Hu