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Traced monoidal categories are used to model processes that can feed their outputs back to their own inputs, abstracting iteration. The category of finite dimensional Hilbert spaces with the direct sum tensor is not traced. But…

Category Theory · Mathematics 2026-02-18 Aaron David Fairbanks , Peter Selinger

We show how to construct a Gamma-bicategory from a symmetric monoidal bicategory, and use that to show that the classifying space is an infinite loop space upon group completion. We also show a way to relate this construction to the classic…

Algebraic Topology · Mathematics 2013-08-29 Angélica Osorno

We provide a new characterisation of quantum supermaps in terms of an axiom that refers only to sequential and parallel composition. Consequently, we generalize quantum supermaps to arbitrary monoidal categories and operational…

Quantum Physics · Physics 2026-03-11 Matt Wilson , Giulio Chiribella , Aleks Kissinger

It is well-known that combinatorial circuits are modeled mathematically by string diagrams in a monoidal category. Given a gate set $\Sigma$, the circuits over $\Sigma$ can be thought of as string diagrams in the free monoidal category…

Quantum Physics · Physics 2025-01-23 Scott Wesley

This article is intended as a reference guide to various notions of monoidal categories and their associated string diagrams. It is hoped that this will be useful not just to mathematicians, but also to physicists, computer scientists, and…

Category Theory · Mathematics 2012-07-31 Peter Selinger

Applied category theory often studies symmetric monoidal categories (SMCs) whose morphisms represent open systems. These structures naturally accommodate complex wiring patterns, leveraging (co)monoidal structures for splitting and merging…

Category Theory · Mathematics 2026-03-11 Marius Furter , Yujun Huang , Gioele Zardini

Calculi of string diagrams are increasingly used to present the syntax and algebraic structure of various families of circuits, including signal flow graphs, electrical circuits and quantum processes. In many such approaches, the semantic…

Logic in Computer Science · Computer Science 2017-05-30 Brendan Fong , Fabio Zanasi

We compute $M$-point conformal blocks with scalar external and exchange operators in the so-called comb configuration for any $M$ in any dimension $d$. Our computation involves repeated use of the operator product expansion to increase the…

High Energy Physics - Theory · Physics 2020-09-22 Jean-François Fortin , Wenjie Ma , Witold Skiba

We implement a novel representation of model search spaces as diagrams over a category of models, where we have restricted attention to a broad class of models whose structure is presented by \C-sets. (Co)limits in these diagram categories…

Logic in Computer Science · Computer Science 2022-06-20 Kristopher Brown , Tyler Hanks , James Fairbanks

We introduce a new type of diagrams and prove the existence of a particular one, the "central tuned diagram", with some optimal features, for finitely generated modules of certain categories. This is achieved by getting to the idea of "the…

Representation Theory · Mathematics 2016-05-31 Stephanos Gekas

Thomason's Homotopy Colimit Theorem has been extended to bicategories and this extension can be adapted, through the delooping principle, to a corresponding theorem for diagrams of monoidal categories. In this version, we show that the…

Category Theory · Mathematics 2011-03-24 A. R. Garzón , R. Pérez

Given a category with a bifunctor and natural isomorphisms for associativity, commutativity and left and right identity we do not assume that extra constraining diagrams hold. We introduce groupoids of coupling trees to describe a version…

Category Theory · Mathematics 2007-05-23 W. P. Joyce

Cube categories are used to encode higher-dimensional categorical structures. They have recently gained significant attention in the community of homotopy type theory and univalent foundations, where types carry the structure of such higher…

Logic in Computer Science · Computer Science 2020-07-21 Gun Pinyo , Nicolai Kraus

We study Morse theory on noncompact manifolds equipped with exhaustions by compact pieces, defining the Morse homology of a pair which consists of the manifold and related geometric/homotopy data. We construct a collection of Morse data…

Geometric Topology · Mathematics 2019-11-12 Taesu Kim

The first part of the paper explains how to encode a one-cocycle and a two-cocycle on a group $G$ with values in its representation by networks of planar trivalent graphs with edges labelled by elements of $G$, elements of the…

K-Theory and Homology · Mathematics 2024-10-10 Mee Seong Im , Mikhail Khovanov

Game comonads provide a categorical syntax-free approach to finite model theory, and their Eilenberg-Moore coalgebras typically encode important combinatorial parameters of structures. In this paper, we develop a framework whereby the…

Logic in Computer Science · Computer Science 2024-02-14 Samson Abramsky , Luca Reggio

We present a method for optimizing quantum circuits architecture. The method is based on the notion of "quantum comb", which describes a circuit board in which one can insert variable subcircuits. The method allows one to efficiently…

Quantum Physics · Physics 2008-09-08 Giulio Chiribella , Giacomo Mauro D'Ariano , Paolo Perinotti

In this paper we adapt previous work on rewriting string diagrams using hypergraphs to the case where the underlying category has a traced comonoid structure, in which wires can be forked and the outputs of a morphism can be connected to…

Logic in Computer Science · Computer Science 2026-01-14 Dan R. Ghica , George Kaye

This paper lays some of the foundations for working with not-necessarily-commutative bialgebras and their categories of comodules in $\infty$-categories. We prove that the categories of comodules and modules over a bialgebra always admit…

Algebraic Topology · Mathematics 2021-08-20 Jonathan Beardsley

Let $\mathcal C$ be a category with finite colimits, and let $(\mathcal E,\mathcal M)$ be a factorisation system on $\mathcal C$ with $\mathcal M$ stable under pushouts. Writing $\mathcal C;\mathcal M^{\mathrm{op}}$ for the symmetric…

Category Theory · Mathematics 2017-03-30 Brendan Fong