Results 61 to 70 of about 262,182 (221)

Topological and metric entropy for group and semigroup actions

Topological Algebra and its Applications, 2019
It is well-known that the classical definition of topological entropy for group and semigroup actions is frequently zero in some rather interesting situations, e.g. smooth actions of ℤk+ (k >1) on manifolds.
Stoyanov Luchezar
doaj   +1 more source

Complete Invariant ⋆-Metrics on Semigroups and Groups

Axioms, 2022
In this paper, we study the complete ⋆-metric semigroups and groups and the Raǐkov completion of invariant ⋆-metric groups. We obtain the following. (1) Let (X,d⋆) be a complete ⋆-metric space containing a semigroup (group) G that is a dense subset of X.
Shi-Yao He, Jian-Cai Wei, Li-Hong Xie
doaj   +1 more source

Stochastic Dynamics From Maximum Entropy in Action Space

Fortschritte der Physik, Volume 74, Issue 5, May 2026.
ABSTRACT We develop an information‐theoretic formulation of stochastic dynamics in which the fundamental stochastic variable is the total action connecting spacetime points, rather than individual paths. By maximizing Shannon entropy over a joint distribution of actions and endpoints, subject to normalization and a constraint on the mean action, we ...
Fabricio Souza Luiz, José Carlos Bellizotti Souza, Luísa Toledo Tude, Marcos César de Oliveira   +3 more
wiley   +1 more source

Algebraic singular functions are not always dense in the ideal of C∗$C^*$‐singular functions

Bulletin of the London Mathematical Society, Volume 58, Issue 5, May 2026.
Abstract We give the first examples of étale (non‐Hausdorff) groupoids G$\mathcal {G}$ whose C∗$C^*$‐algebras contain singular elements that cannot be approximated by singular elements in Cc(G)$\mathcal {C}_c(\mathcal {G})$. We provide two examples: one is a bundle of groups and the other a minimal and effective groupoid constructed from a self‐similar
Diego Martínez, Nóra Szakács
wiley   +1 more source

The group of characters of a pseudocompact locally compact semitopological semigroup

Applied General Topology
We prove that each semitopological semigroup has a reflection in the class of abelian cancellative semitopological semigroups. Then we use this reflection to prove that the group of characters of a locally compact pseudocompact topological semigroup with
Julio César Hernández Arzusa
doaj   +1 more source

Embedding of topological semigroups in simple semigroups

Matematychni Studii, 1994
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
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Existence of viscosity solutions to abstract Cauchy problems via nonlinear semigroups

Bulletin of the London Mathematical Society, Volume 58, Issue 5, May 2026.
Abstract In this work, we provide conditions for nonlinear monotone semigroups on locally convex vector lattices to give rise to a generalized notion of viscosity solutions to a related nonlinear partial differential equation. The semigroup needs to satisfy a convexity estimate, so called K$K$‐convexity, with respect to another family of operators ...
Fabian Fuchs, Max Nendel
wiley   +1 more source

On the closure of the extended bicyclic semigroup

Karpatsʹkì Matematičnì Publìkacìï, 2011
In the paper we study the semigroup $mathscr{C}_{mathbb{Z}}$which is a generalization of the bicyclic semigroup. We describemain algebraic properties of the semigroup$mathscr{C}_{mathbb{Z}}$ and prove that every non-trivialcongruence $mathfrak{C}$ on the
I. R. Fihel, O. V. Gutik
doaj  

HNN extensions and embedding theorems for groups

Journal of the London Mathematical Society, Volume 113, Issue 5, May 2026.
Abstract The Higman–Neumann–Neumann (HNN) paper of 1949 is a landmark of group theory in the 20th century. The proof of its main theorem covers less than a page and uses only pre‐existing technology, but the construction that it introduced, the HNN extension, quickly became one of the principal tools of combinatorial group theory, widely used to build ...
Martin R. Bridson, Carl‐Fredrik Nyberg‐Brodda   +1 more
wiley   +1 more source

On topological McAlister semigroups

Journal of Pure and Applied Algebra, 2023
In this paper we consider McAlister semigroups over arbitrary cardinals and investigate their algebraic and topological properties. We show that the group of automorphisms of a McAlister semigroup $\mathcal{M}_λ$ is isomorphic to the direct product $Sym(λ){\times}\mathbb{Z}_2$, where $Sym(λ)$ is the group of permutations of the cardinal $λ$.
openaire   +2 more sources