Onto extensions of free groups

Autor: Sebastià Mijares, Enric Ventura

Publikováno v: Groups, Complexity, Cryptology, Vol Volume 13, Issue 1 (2021)

An extension of subgroups $H\leqslant K\leqslant F_A$ of the free group of rank $|A|=r\geqslant 2$ is called onto when, for every ambient free basis $A'$, the Stallings graph $\Gamma_{A'}(K)$ is a quotient of $\Gamma_{A'}(H)$. Algebraic extensions ar

Externí odkaz: https://doaj.org/article/f557a5f538a1484cb39d3c2b3ee3ec64

Stallings automata for free-times-abelian groups : intersections and index

Autor: Jordi Delgado, Enric Ventura

Publikováno v: Dipòsit Digital de Documents de la UAB
Universitat Autònoma de Barcelona

We extend the classical Stallings theory (describing subgroups of free groups as automata) to direct products of free and abelian groups: after introducing enriched automata (i.e., automata with extra abelian labels), we obtain an explicit bijection

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::f93e494d966dbfa24fe9c4bb4fb6b73c
https://ddd.uab.cat/record/264540

Orbit decidability and the conjugacy problem for some extensions of groups

Autor: Oleg Bogopolski, Enric Ventura, Armando Martino

Publikováno v: Recercat: Dipósit de la Recerca de Catalunya
Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
Recercat. Dipósit de la Recerca de Catalunya
instname
Dipòsit Digital de Documents de la UAB
Universitat Autònoma de Barcelona

Given a short exact sequence of groups with certain conditions, 1 → F → G → H → 1 1\rightarrow F\rightarrow G\rightarrow H\rightarrow 1 , we prove that G G has solvable conjugacy problem if and only if the corresponding action subgroup A ⩽

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::ecf64acea5756fb55eeaab0afee58cee
http://hdl.handle.net/2072/418741

Degrees of compression and inertia for free-abelian times free groups

Autor: Enric Ventura, Mallika Roy

Publikováno v: UPCommons. Portal del coneixement obert de la UPC
Universitat Politècnica de Catalunya (UPC)

© 2020. Elsevier We introduce the concepts of degree of inertia, diG(H), and degree of compression,dcG(H), of a finitely generated subgroupHof a given groupG. For the case of direct productsof free-abelian and free groups, we compute the degree of c

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::da29f18945194f2f6dd5051c46381d54
http://arxiv.org/abs/1901.02922

Algorithmic and Geometric Topics Around Free Groups and Automorphisms

Autor: Javier Aramayona, Volker Diekert, Christopher J. Leininger, Pedro V. Silva, Armin Weiß, Juan González-Meneses, Martin Lustig, Enric Ventura

This volume presents the lecture notes from the authors'three summer courses offered during the program “Automorphisms of Free Groups: Geometry, Topology, and Dynamics,” held at the Centre de Recerca Matemàtica (CRM) in Bellaterra, Spain. The fi