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Abstract. This article determines relations between two notions concerning monoids: factorability structure, introduced to simplify the bar complex; and quadratic normalisation, introduced to generalise quadratic rewriting systems and…

Group Theory · Mathematics 2025-01-03 Alen Đurić

We develop the K-theory of sets with an action of a pointed monoid (or monoid scheme), analogous to the $K$-theory of modules over a ring (or scheme). In order to form localization sequences, we construct the quotient category of a nice…

K-Theory and Homology · Mathematics 2021-09-08 Ian Coley , Charles Weibel

We introduce regular languages of morphisms in free monoidal categories, with their associated grammars and automata. These subsume the classical theory of regular languages of words and trees, but also open up a much wider class of…

Formal Languages and Automata Theory · Computer Science 2022-07-04 Matthew Earnshaw , Paweł Sobociński

We introduce and study Hopf monads on autonomous categories (i.e., monoidal categories with duals). Hopf monads generalize Hopf algebras to a non-braided (and non-linear) setting. Indeed, any monoidal adjunction between autonomous…

Quantum Algebra · Mathematics 2007-05-23 Alain Bruguières , Alexis Virelizier

For any morphism of $\infty$-operads $\mathcal{P} \to \mathcal{O}$, we show that the free $\mathcal{O}$-algebra on a $\mathcal{P}$-algebra admits an explicit formula as the colimit over the $\mathcal{O}$-monoidal envelope of $\mathcal{P}$,…

Category Theory · Mathematics 2026-05-06 Max Blans , Sil Linskens

In this paper we consider endomorphisms of an undirected cycle graph from Semigroup Theory perspective. Our main aim is to present a process to determine sets of generators with minimal cardinality for the monoids $wEnd(C_n)$ and $End(C_n)$…

Rings and Algebras · Mathematics 2023-10-09 Ilinka Dimitrova , Vítor H. Fernandes , Jörg Koppitz , Teresa M. Quinteiro

Polynomials in a category have been studied as a generalization of the traditional notion in mathematics. Their construction has recently been extended to higher groupoids, as formalized in homotopy type theory, by Finster, Mimram, Lucas…

Category Theory · Mathematics 2024-12-18 Elies Harington , Samuel Mimram

Combining the definition of 0-Hecke monoids with that of Kiselman semigroups, we define what we call Kiselman quotients of 0-Hecke monoids associated with simply laced Dynkin diagrams. We classify these monoids up to isomorphism, determine…

Group Theory · Mathematics 2011-07-26 Olexandr Ganyushkin , Volodymyr Mazorchuk

A Mauldin-Williams graph $\mathcal{M}$ is a generalization of an iterated function system by a directed graph. Its invariant set $K$ plays the role of the self-similar set. We associate a $C^{*}$-algebra $\mathcal{O}_{\mathcal{M}}(K)$ with…

Operator Algebras · Mathematics 2007-05-23 Marius Ionescu , Yasuo Watatani

There are different notions of computation, the most popular being monads, applicative functors, and arrows. In this article we show that these three notions can be seen as monoids in a monoidal category. We demonstrate that at this level…

Logic in Computer Science · Computer Science 2014-06-19 Exequiel Rivas , Mauro Jaskelioff

The purpose of this paper is to give new examples of families of free singularities. We first show that a generic equidimensional subspace arrangement is free. Furthermore, we show that a product of two reduced Cohen-Macaulay subspaces is…

Algebraic Geometry · Mathematics 2020-12-23 Raul Epure , Delphine Pol

A variety of universal algebras is called limit if it is non-finitely based but all its proper subvarieties are finitely based. Until recently, only two explicit examples of limit varieties of monoids, constructed by Jackson, were known.…

Group Theory · Mathematics 2020-08-11 S. V. Gusev

The aim of this paper is to describe the definitions and main properties of three generalizations of the group concept, namely: groupoid, generalized group and almost groupoid. Some constructions of these algebraic structures and…

Group Theory · Mathematics 2025-11-03 Gheorghe Ivan

We prove (using grammars) that the free inverse monoid of every finite rank has co-context-free word problem. Equivalently, the co-word problem of the free inverse monoid of every finite rank is context-free.

We generalize the Brin-Higman-Thompson groups $n G_{k,1}$ to monoids $n M_{k,1}$, for $n \ge 1$ and $k \ge 2$, by replacing bijections by partial functions. The monoid $n M_{k,1}$ has $n G_{k,1}$ as its group of units, and is…

Group Theory · Mathematics 2020-06-30 J. C. Birget

In this paper we modify and generalize a construction presented by Novotn\'y: given a groupoid (a set equipped with a binary operation), it is defined a mono-unary algebra corresponding to that specific groupoid. We shall introduce and…

Rings and Algebras · Mathematics 2018-03-07 Hilário Fernandes de Araújo Júnior

We define a free product of connected simple graphs that is equivalent to several existing definitions when the graphs are vertex-transitive but differs otherwise. The new definition is designed for the automorphism group of the free…

Group Theory · Mathematics 2021-09-30 Max Carter , Stephan Tornier , George A. Willis

We introduce an interesting class of left adequate monoids which we call pretzel monoids. These, on the one hand, are monoids of birooted graphs with respect to a natural `glue-and-fold' operation, and on the other hand, are shown to be…

Rings and Algebras · Mathematics 2024-05-02 Daniel Heath , Mark Kambites , Nóra Szakács

We investigate the notion of soficity for monoids. A group is sofic as a group if and only if it is sofic as a monoid. All finite monoids, all commutative monoids, all free monoids, all cancellative one-sided amenable monoids, all…

Dynamical Systems · Mathematics 2015-05-06 Tullio Ceccherini-Silberstein , Michel Coornaert

The notion of a generalized scale emerged in recent joint work with Afsar-Brownlowe-Larsen on equilibrium states on C*-algebras of right LCM monoids, where it features as the key datum for the dynamics under investigation. This work…

Group Theory · Mathematics 2019-03-25 Nicolai Stammeier