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A monoid $S$ is right coherent if every finitely generated subact of every finitely presented right $S$-act itself has a finite presentation; it is weakly right coherent if every finitely generated right ideal of $S$ has a finite…

Rings and Algebras · Mathematics 2023-12-22 Matthew Brookes , Victoria Gould , Nik Ruskuc

We show that the freeness problems for automaton semigroups and for automaton monoids are undecidable and, thereby, solve an open problem listed by Grigorchuk, Nekrashevych and Sush\-chansk\u{\i}i. We achieve this using a new technique to…

Formal Languages and Automata Theory · Computer Science 2025-02-19 Daniele D'Angeli , Emanuele Rodaro , Jan Philipp Wächter

We initiate the study of the expansion $\mathcal{S}(M)$ of a monoid $M$ obtained via the semidirect product of $M$ acting naturally on the left of its power set (regarded as a semilattice under union). We term this the `subset expansion' of…

Rings and Algebras · Mathematics 2025-12-22 Victoria Gould , Marianne Johnson

In this paper, we introduce and investigate monadic NM-algebras: a variety of NM-algebras equipped with universal quantifiers. Also, we obtain some conditions under which monadic NM-algebras become monadic Boolean algebras. Besides, we show…

Logic · Mathematics 2017-09-15 Jun Tao Wang , Xiao Long Xin , Peng Fei He

This paper introduces and studies a categorical analogue of the familiar monoid semiring construction. By introducing an axiomatisation of summation that unifies notions of summation from algebraic program semantics with various notions of…

Category Theory · Mathematics 2013-06-03 Peter Hines

We present a comonadic approach to pretorsion theories on semiexact categories, i.e. categories equipped with a closed ideal of null morphisms that admits all kernels and all cokernels. We first prove that bihereditary pretorsion theories…

Category Theory · Mathematics 2026-01-19 Elena Caviglia , Zurab Janelidze , Luca Mesiti

This paper proposes a general semantic framework for verifying programs with arbitrary monadic side-effects using Dijkstra monads, which we define as monad-like structures indexed by a specification monad. We prove that any monad morphism…

Programming Languages · Computer Science 2019-06-27 Kenji Maillard , Danel Ahman , Robert Atkey , Guido Martinez , Catalin Hritcu , Exequiel Rivas , Éric Tanter

We introduce rational semimodules over semirings whose addition is idempotent, like the max-plus semiring, in order to extend the geometric approach of linear control to discrete event systems. We say that a subsemimodule of the free…

Optimization and Control · Mathematics 2007-05-23 Stephane Gaubert , Ricardo Katz

Over the past two decades the notion of a strong monad has found wide applicability in computing. Arising out of a need to interpret products in computational and semantic settings, different approaches to this concept have arisen. In this…

Programming Languages · Computer Science 2013-09-23 Philip Mulry

In this article we discuss some applications of the construction of the Ap\'ery set of a good semigroup in $\mathbb{N}^d$ given in the previous paper [Partition of the complement of good semigroup ideals and Ap\'ery sets, Communications in…

Combinatorics · Mathematics 2022-04-12 Lorenzo Guerrieri , Nicola Maugeri , Vincenzo Micale

We consider the canonical pseudodistributive law between various free limit completion pseudomonads and the free coproduct completion pseudomonad. When the class of limits includes pullbacks, we show that this consideration leads to notions…

Category Theory · Mathematics 2024-06-13 Fernando Lucatelli Nunes , Rui Prezado , Matthijs Vákár

In this paper we study the representation of Morse polynomial functions which are nonnegative on a compact basic closed semi-algebraic set in $\mathbb R^n$, and having only finitely many zeros in this set. Following C. Bivi\`{a}-Ausina, we…

Algebraic Geometry · Mathematics 2019-02-19 Công-Trình Lê

For some numerical semigroup rings of small embedding dimension, namely those of embedding dimension 3, and symmetric or pseudosymmetric of embedding dimension 4, presentations has been determined in the literature. We extend these results…

Commutative Algebra · Mathematics 2013-09-11 Valentina Barucci , Ralf Fröberg , Mesut Sahin

One of the main reasons for the correspondence of regular languages and monadic second-order logic is that the class of regular languages is closed under images of surjective letter-to-letter homomorphisms. This closure property holds for…

Logic in Computer Science · Computer Science 2022-01-26 Mikołaj Bojańczyk , Bartek Klin , Julian Salamanca

Recent algorithmic advances in algebraic automata theory drew attention to semigroupoids (semicategories). These are mathematical descriptions of typed computational processes, but they have not been studied systematically in the context of…

Formal Languages and Automata Theory · Computer Science 2025-09-30 Attila Egri-Nagy , Chrystopher L. Nehaniv

By considering the situation in which the involved pseudomonads are presented in no-iteration form, we deduce a number of alternative presentations of pseudodistributive laws including a 'decagon' form, a pseudoalgebra form, a no-iteration…

Category Theory · Mathematics 2025-01-06 Charles Walker

We define and explore semireflection monoids on a finite-dimensional vector space. These are monoids generated by semireflections: linear maps fixing a subspace of codimension 1. We mostly focus on the case of projection monoids (where the…

Group Theory · Mathematics 2026-03-31 Matthew Fayers

We present a coalgebraic generalisation of Fischer and Ladner's Propositional Dynamic Logic (PDL) and Parikh's Game Logic (GL). In earlier work, we proved a generic strong completeness result for coalgebraic dynamic logics without…

Logic in Computer Science · Computer Science 2016-08-08 Helle Hvid Hansen , Clemens Kupke

In this paper we introduce a model theoretic construction for the theories of uniform layered domains and semifields introduced in the paper of Izhakian, Knebusch and Rowen. We prove that, for a given layering semiring L, the theory of…

Algebraic Geometry · Mathematics 2013-05-21 Tal Perri

Distributive laws give a way of combining two algebraic structures expressed as monads; in this paper we propose a theory of distributive laws for combining algebraic structures expressed as Lawvere theories. We propose four approaches,…

Category Theory · Mathematics 2024-08-07 Eugenia Cheng