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Related papers: Inverse semigroup shifts over countable alphabets

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The index of a subgroup of a group counts the number of cosets of that subgroup. A subgroup of finite index often shares structural properties with the group, and the existence of a subgroup of finite index with some particular property can…

Group Theory · Mathematics 2016-08-16 Amal AlAli , N. D. Gilbert

Various kinds of infinitary operations satisfying forms of associativity have been considered in the literature by various authors, including A. Tarski, C. Karp, J. H. Conway, D. Krob, N. Bedon, and C. Rispal. Applications include the…

Group Theory · Mathematics 2026-05-28 Paolo Lipparini

In this paper, we study algorithmic problems for automaton semigroups and automaton groups related to freeness and finiteness. In the course of this study, we also exhibit some connections between the algebraic structure of automaton…

Formal Languages and Automata Theory · Computer Science 2020-04-10 Daniele D'Angeli , Emanuele Rodaro , Jan Philipp Wächter

A shift-invariant space is a space of functions that is invariant under integer translations. Such spaces are often used as models for spaces of signals and images in mathematical and engineering applications. This paper characterizes those…

Functional Analysis · Mathematics 2010-07-07 Akram Aldroubi , Carlos Cabrelli , Christopher Heil , Keri Kornelson , Ursula Molter

We introduce invertible subalgebras of local operator algebras on lattices. An invertible subalgebra is defined to be one such that every local operator can be locally expressed by elements of the inveritible subalgebra and those of the…

Mathematical Physics · Physics 2023-11-06 Jeongwan Haah

Given a one-sided subshift $X$ on a finite alphabet, we consider the semigroup $S_X =L_X \cup \{0\}$, where $L_X $ is the language of $X $, equipped with the multiplication operation given by concatenation, when allowed, and set to vanish…

Operator Algebras · Mathematics 2019-08-23 R. Exel , B. Steinberg

The purpose of this paper is to study the generalization of inverse semigroups (without order). An ordered semigroup S is called an inverse ordered semigroup if for every a 2 S, any two inverses of a are H-related. We prove that an ordered…

Group Theory · Mathematics 2019-05-13 A. Jamadar , K. Hansda

In this paper, we present new necessary and sufficient conditions under which the sum of two group invertible elements in a Banach algebra has group inverse. We then apply these results to block operator matrices over Banach spaces. The…

Functional Analysis · Mathematics 2022-03-16 Huanyin Chen , Marjan Sheibani

Let $\E$ be a finite dimensional Hilbert space. This note finds all factorizations of the right shift semigroup $\S^\E=(S_t^\E)_{t\ge 0}$ on $L^2(\R_+,\E)$ into the product of $n$ commuting contractive semigroups, i.e., characterizes all…

Functional Analysis · Mathematics 2026-02-03 Tirthankar Bhattacharyya , Shubham Rastogi , Kalyan B. Sinha , Vijaya Kumar U

In the following text we compute the adjoint of weighted generalized shift operators over Hilbert spaces. We show for a conjugate invariant subset $A$ of $\mathbb C$, the additive semigroup generated by $A\cup\{0\}-$weighted generalized…

Functional Analysis · Mathematics 2024-04-02 F. Ayatollah Zadeh Shirazi , E. Hakimi , A. Hosseini , R. Rezavand

The Medvedev degree of a subshift is a dynamical invariant of computable origin that can be used to compare the complexity of subshifts that contain only uncomputable configurations. We develop theory to describe how these degrees can be…

Dynamical Systems · Mathematics 2026-05-11 Sebastián Barbieri , Nicanor Carrasco-Vargas

We define a notion of (one-sided) edge shift spaces associated to ultragraphs. In the finite case our notion coincides with the edge shift space of a graph. In general, we show that our space is metrizable and has a countable basis of…

Operator Algebras · Mathematics 2017-05-19 Daniel Gonçalves , Danilo Royer

We prove that every bounded, positive, irreducible, stochastically continuous semigroup on the space of bounded, measurable functions which is strong Feller, consists of kernel operators and possesses an invariant measure converges…

Functional Analysis · Mathematics 2012-02-03 Moritz Gerlach , Robin Nittka

For upper semi-continuous potentials defined on shifts over countable alphabets, this paper ensures sufficient conditions for the existence of a maximizing measure. We resort to the concept of blur shift, introduced by T. Almeida and M.…

Dynamical Systems · Mathematics 2026-04-29 Eduardo Garibaldi , João T A Gomes , Marcelo Sobottka

In this paper we study the shifts, which are the shift-invariant and topologically closed sets of configurations over a finite alphabet in $\mathbb{Z}^d$. The minimal shifts are those shifts in which all configurations contain exactly the…

Discrete Mathematics · Computer Science 2017-06-27 Bruno Durand , Andrei Romashchenko

In the paper we study (countably) compact and (absolutely) $H$-closed primitive topological inverse semigroups. We describe the structure of compact and countably compact primitive topological inverse semigroups and show that any countably…

Group Theory · Mathematics 2010-05-25 Tetyana Berezovski , Oleg Gutik , Kateryna Pavlyk

We characterize the inverse semigroups that are Morita equivalent to graph inverse semigroups. We also consider a generalization to inverse semigroups associated with left cancellative categories.

Group Theory · Mathematics 2023-07-25 Martha Du Preez , Robert Grimley , Evan Lira , David Milan , Shreyas Ramamurthy

In this paper we construct free Hom-semigroups when its unary operation is multiplicative and is an involution. Our method of construction is by bracketed words. As a consequence, we obtain free Hom-associative algebras generated by a set…

Rings and Algebras · Mathematics 2017-12-19 Li Guo , Shanghua Zheng

Let $(X_A,\sigma_A)$ be the right one-sided topological Markov shift for an irreducible matrix with entries in $\{0,1\}$, and $\Gamma_A$ the continuous full group of $(X_A,\sigma_A)$. For two irreducible matrices $A$ and $B$ with entries in…

Operator Algebras · Mathematics 2012-05-08 Kengo Matsumoto

By analytic perturbations, we refer to shifts that are finite rank perturbations of the form $M_z + F$, where $M_z$ is the unilateral shift and $F$ is a finite rank operator on the Hardy space over the open unit disc. Here shift refers to…

Functional Analysis · Mathematics 2021-07-13 Susmita Das , Jaydeb Sarkar