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In this survey, we address the worst-case, average-case, and generic-case time complexity of the word problem and some other algorithmic problems in several classes of groups and show that it is often the case that the average-case…

Group Theory · Mathematics 2024-01-18 Vladimir Shpilrain

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

Let E be a number field and G be a finite group. Let A be any O_E-order of full rank in the group algebra E[G] and X be a (left) A-lattice. In a previous article, we gave a necessary and sufficient condition for X to be free of given rank d…

Number Theory · Mathematics 2010-09-16 Werner Bley , Henri Johnston

We adapt the Deutsch-Josza algorithm to the context of formal language theory. Specifically, we use the algorithm to distinguish between trivial and nontrivial words in groups given by finite presentations, under the promise that a word is…

Quantum Physics · Physics 2008-02-05 Michael Batty , Andrea Casaccino , Andrew J. Duncan , Sarah Rees , Simone Severini

To any free group automorphism, we associate a real pretree with several nice properties. First, it has a rigid/non-nesting action of the free group with trivial arc stabilizers. Secondly, there is an expanding pretree-automorphism of the…

Group Theory · Mathematics 2024-05-29 Jean Pierre Mutanguha

We investigate analytically the problem of enumeration of nonequivalent primitive words in the braid group B_n for n >> 1 by analysing the random word statistics and the target space on the basis of the locally free group approximation. We…

Statistical Mechanics · Physics 2009-10-30 Alain Comtet , Sergei Nechaev

Distances are fundamental primitives whose choice significantly impacts the performances of algorithms in machine learning and signal processing. However selecting the most appropriate distance for a given task is an endeavor. Instead of…

Machine Learning · Computer Science 2020-10-01 Frank Nielsen , Richard Nock

We describe a novel algorithm for random sampling of freely reduced words equal to the identity in a finitely presented group. The algorithm is based on Metropolis Monte Carlo sampling. The algorithm samples from a stretched Boltzmann…

Group Theory · Mathematics 2013-12-23 M. Elder , A. Rechnitzer , E. J. Janse van Rensburg

A conjecture of Dicks and the author on rank of the intersection of factor-free subgroups in free products of groups is proved for the case of left ordered groups.

Group Theory · Mathematics 2016-07-12 Sergei V. Ivanov

We establish that, under certain closure assumptions on a pseudovariety of semigroups, the corresponding relatively free profinite semigroups freely generated by a non-singleton finite set act faithfully on their minimum ideals. As…

Group Theory · Mathematics 2020-09-15 J. Almeida , O. Klíma

The present paper records more details of the relationship between primitive elements and palindromes in F_2, the free group of rank two. We characterise the conjugacy classes of primitive elements which contain palindromes as those which…

Group Theory · Mathematics 2019-02-07 Adam Piggott

We use the generating function approach to derive simple expressions for the factorial moments of the distance distribution over Reed-Solomon codes. We obtain better upper bounds for the error term of a counting formula given by Li and Wan,…

Information Theory · Computer Science 2022-05-06 Zhicheng Gao , Jiyou Li

In large datasets, it is hard to discover and analyze structure. It is thus common to introduce tags or keywords for the items. In applications, such datasets are then filtered based on these tags. Still, even medium-sized datasets with a…

Machine Learning · Computer Science 2023-02-23 Dominik Dürrschnabel , Gerd Stumme

Recently, we have introduced and studied the topic of sub-indices and sub-factors of groups. During those studies, an algorithm for obtaining the sub-factors of a finite group was stated and proved, which has a particular case for…

Group Theory · Mathematics 2023-04-05 M. H. Hooshmand

Separability for groups refers to the question which subsets of a group can be detected in its finite quotients. Classically, separability is studied in terms of which classes have a certain separability property, and this question is…

Group Theory · Mathematics 2022-02-01 Jonas Deré , Michal Ferov , Mark Pengitore

With each semigroup one can associate a partial algebra, called the biordered set, which captures important algebraic and geometric features of the structure of idempotents of that semigroup. For a biordered set $\mathcal{E}$, one can…

Group Theory · Mathematics 2022-10-07 Igor Dolinka

Randomized rankings have been of recent interest to achieve ex-ante fairer exposure and better robustness than deterministic rankings. We propose a set of natural axioms for randomized group-fair rankings and prove that there exists a…

Machine Learning · Computer Science 2023-05-30 Sruthi Gorantla , Amit Deshpande , Anand Louis

We describe an algorithm which determines whether or not a group which is hyperbolic relative to abelian groups admits a nontrivial splitting over a finite group.

Group Theory · Mathematics 2009-03-19 Francois Dahmani , Daniel Groves

Under reasonable assumptions, a group action on a module extends to the minimal free resolutions of the module. Explicit descriptions of these actions can lead to a better understanding of free resolutions by providing, for example,…

Commutative Algebra · Mathematics 2021-11-05 Federico Galetto

We adapt the Ping-Pong Lemma, which historically was used to study free products of groups, to the setting of the homeomorphism group of the unit interval. As a consequence, we isolate a large class of generating sets for subgroups of…