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In this paper we discuss graph inverse semigroups which are constucted from a directed graphs and study several interesting properties of graph inverse semigroups such as the nature of its idempotents, the structure of semilattice of…

Group Theory · Mathematics 2020-04-07 P G Romeo , Alanka Thomas

We consider semigroups of Ruelle-expanding maps, parameterized by random walks on the free semigroup, with the aim of examining their complexity and exploring the relation between intrinsic properties of the semigroup action and the…

Dynamical Systems · Mathematics 2017-02-01 Maria Carvalho , Fagner B. Rodrigues , Paulo Varandas

We consider exponential ultradistribution semigroups with non--densely defined generators and give structural theorems for ultradistribution semigroups. Also structural theorems for exponential ultradistribution semigroups are given.

Functional Analysis · Mathematics 2013-06-06 Marko Kostić , Stevan Pilipović , Daniel Velinov

In this paper, we discuss some well-known results and some open problems of the theory of $\sigma$-properties of a group related to the study of generalized $T$-groups.

Group Theory · Mathematics 2023-02-28 Inna N. Safonova , Alexander N. Skiba

This note relates axioms for partial semigroups and monoids with those for small object-free categories, either with multiple monoidal units or with source and target maps. We discuss the adjunction of a zero element to both kinds of…

Logic in Computer Science · Computer Science 2020-02-03 James Cranch , Simon Doherty , Georg Struth

This article highlights historical achievements in the partition theory of countable homogeneous relational structures, and presents recent work, current trends, and open problems. Exciting recent developments include new methods involving…

Logic · Mathematics 2021-10-05 Natasha Dobrinen

We investigate classifications of quasitrivial semigroups defined by certain equivalence relations. The subclass of quasitrivial semigroups that preserve a given total ordering is also investigated. In the special case of finite semigroups,…

Rings and Algebras · Mathematics 2020-05-21 Jimmy Devillet , Jean-Luc Marichal , Bruno Teheux

We survey some results that provide different versions of classical results through different summability methods. Specifically, in order to adapt such classical results, we analyze which properties should satisfy the summability methods.…

We present a generation theorem for positive semigroups on an $L^1$ space. It provides sufficient conditions for the existence of positive and integrable solutions of initial-boundary value problems. An application to a two-phase cell cycle…

Functional Analysis · Mathematics 2020-06-03 Piotr Gwiżdż , Marta Tyran-Kamińska

Using the notion of existentially closed structures, we obtain embedding theorems for groups and Lie algebras. We also prove the existence of some groups and Lie algebras with prescribed properties.

Group Theory · Mathematics 2014-05-07 M. Shahryari

In this paper, we construct a new homology theory for semi-groups satisfying the self distributivity axiom or the idempotency axiom. Next, we consider the geometric realization corresponding to the homology theory. We continue with the…

Geometric Topology · Mathematics 2016-11-18 Sujoy Mukherjee

We introduce so-called cone topologies of paratopological groups, which are a wide way to construct counterexamples, especially of examples of compact-like paratopological groups with discontinuous inversion. We found a simple interplay…

Group Theory · Mathematics 2019-08-08 Alex Ravsky

Broadly speaking, a finiteness property of groups is any generalisation of the property of having finite order. A large part of infinite group theory is concerned with finiteness properties and the relationships between them. Profinite…

Group Theory · Mathematics 2010-02-16 Colin Reid

Positive $C_0$-semigroups that occur in concrete applications are, more often than not, irreducible. Therefore a deep and extensive theory of irreducibility has been developed that includes characterizations, perturbation analysis, and…

Functional Analysis · Mathematics 2024-06-28 Sahiba Arora , Jochen Glück

This paper studies the classes of semigoups and monoids with context-free and deterministic context-free word problem. First, some examples are exhibited to clarify the relationship between these classes and their connection with the…

Group Theory · Mathematics 2019-03-26 Tara Brough , Alan J. Cain , Markus Pfeiffer

We introduce a misere quotient semigroup construction in impartial combinatorial game theory, and argue that it is the long-sought natural generalization of the normal-play Sprague-Grundy theory to misere play. Along the way, we illustrate…

Combinatorics · Mathematics 2007-05-23 Thane E. Plambeck

We consider the logic space of countable (enumerated) groups and show that closed subspaces corresponding to some standard classes of groups have (do not have) generic groups. We also discuss the cases of semigroups and associative rings.

Logic · Mathematics 2025-12-03 Aleksander Ivanov , Krzysztof Majcher

We prove a structure result on proper extensions of two-sided restriction semigroups in terms of partial actions, generalizing respective results for monoids and for inverse semigroups and upgrading the latter. We introduce and study…

Rings and Algebras · Mathematics 2024-10-29 Mikhailo Dokuchaev , Mykola Khrypchenko , Ganna Kudryavtseva

We determine, up to the equivalence of first-order interdefinability, all structures which are first-order definable in the random partial order. It turns out that these structures fall into precisely five equivalence classes. We achieve…

In this paper we develop an ideal structure theory for the class of left reductive regular semigroups and apply it to several subclasses of popular interest. In these classes we observe that the right ideal structure of the semigroup is…

Group Theory · Mathematics 2025-12-17 P. A. Azeef Muhammed , Gracinda M. S. Gomes