Exploració per autor "Ventura Capell, Enric"
Ara es mostren els items 53-72 de 72
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Group-theoretic orbit decidability
Ventura Capell, Enric (De Gruytr, 2014-12-01)
Article
Accés obertA recent collection of papers in the last years have given a renovated interest to the notion of orbit decidability. This is a new quite general algorithmic notion, connecting with several classical results, and closely ... -
Informació i codis
Brunat Blay, Josep Maria; Ventura Capell, Enric (Edicions UPC, 2001)
Llibre
Accés restringit a la comunitat UPCLa teoria de la comunicació té els orígens a mitjan segle XX i cada vegada té més rellevància científica, tecnològica i social. Aquest llibre és una introducció a la matèria i en tracta els dos aspectes principals, la ... -
Intersection configurations in free and free times free-abelian groups
Delgado Rodríguez, Jordi; Roy, Mallika; Ventura Capell, Enric (Cambridge University Press, 2023-09-11)
Article
Accés obertIn this paper, we study intersection configurations – which describe the behaviour of multiple (finite) intersections of subgroups with respect to finite generability – in the realm of free and free times free-abelian ... -
Intersection problem for Droms RAAGs
Delgado Rodríguez, Jorge; Ventura Capell, Enric; Zakharov, Alexander (2018-01-01)
Article
Accés obertWe solve the subgroup intersection problem (SIP) for any RAAG G of Droms type (i.e., with defining graph not containing induced squares or paths of length 3): there is an algorithm which, given finite sets of generators ... -
On automorphism-fixed subgroups of a free group
Martino, Armando; Ventura Capell, Enric (2000-08)
Article
Accés obertLet F be a flnitely generated free group, and let n denote its rank. A subgroup H of F is said to be automorphism-flxed, or auto-flxed for short, if there exists a set S of automorphisms of F such that H is precisely the ... -
On endomorphisms of torsion-free hyperbolic groups
Bogopolski, Oleg; Ventura Capell, Enric (2011-02-10)
Article
Accés obert -
On two distributions of subgroups of free groups
Bassino, Frédérique; Martino, Armando; Nicaud, Cyril; Ventura Capell, Enric; Weil, Pascal (Society for Industrial and Applied Mathematics, 2010)
Text en actes de congrés
Accés restringit per política de l'editorialWe study and compare two natural distributions of finitely generated subgroups of free groups. One is based on the random generation of tuples of reduced words; that is the one classically used by group theorists. The ... -
Onto extensions of free groups
Ventura Capell, Enric; Mijares, Sebastià (2021-04-07)
Article
Accés obertRationale Cocaine addiction is a chronic relapsing disorder that lacks of an effective treatment. Isoflavones are a family of compounds present in different plants and vegetables like soybeans that share a common chemical ... -
Probabilistic nilpotence in infinite groups
Ventura Capell, Enric; Martino, Armando; Tointon, Matthew C.H.; Valiunas, Motiejus (2021-07-02)
Article
Accés obertThe ‘degree of k-step nilpotence’ of a finite group G is the proportion of the tuples (x1,…, xk+1 ¿ Gk+1 for which the simple commutator [x1, …, xk+1] is equal to the identity. In this paper we study versions of this for ... -
Relative order and spectrum in free and related groups
Delgado Rodríguez, Jordi; Ventura Capell, Enric; Zakharov, Alexander (2022-12-19)
Article
Accés obertWe consider a natural generalization of the concept of order of an element in a group: an element g ¿ G is said to have order k in a subgroup H (resp., in a coset Hu) of a group G if k is the first strictly positive integer ... -
Stallings automata and applications : BGSMath graduate course
Delgado Rodríguez, Jordi; Ventura Capell, Enric; Weil, Pascal (2023-02-15)
Report de recerca
Accés obertThe theory of Stallings automata provides a neat geometric representation of subgroups of the free group, and constitutes the modern —and probably the most natural and fruitful — approach to their study. Moreover, if the ... -
Stallings automata for free-times-abelian groups: intersections and index
Delgado Pin, Jordi; Ventura Capell, Enric (2022-06-22)
Article
Accés obertWe 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 ... -
Statistical properties of subgroups of free groups
Bassino, Frederique; Martino, Armando; Nicaud, Cyril; Ventura Capell, Enric; Weil, Pascal (2013-02-04)
Article
Accés obertThe usual way to investigate the statistical properties of finitely generated subgroups of free groups, and of finite presentations of groups, is based on the so-called word-based distribution: subgroups are generated ... -
The automorphism group of a free-by-cyclic group in rank 2
Bogopolski, Oleg; Martino, Armando; Ventura Capell, Enric (2007-05)
Article
Accés obertLet ¡ be an automorphism of a free group F 2 of rank 2 and let M ¡ = F 2 o ¡ Z be the corresponding mapping torus of ¡ . We prove that the group Out ( M ¡ ) is usually virtually cyclic. More- over, ... -
The conjugacy problem for free-by-cyclic groups
Martino, Armando; Ventura Capell, Enric (2004-04)
Report de recerca
Accés obertWe show that the conjugacy problem is solvable in [finitely generated free]-by-cyclic groups, by using a result of O. Maslakova that one can algorithmically find generating sets for the fixed sub- groups of free group ... -
The conjugacy problem in automaton groups is not solvable
Šunic, Z.; Ventura Capell, Enric (2012-08-15)
Article
Accés obert(Free abelian)-by-free, self-similar groups generated by finite self-similar sets of tree automorphisms and having unsolvable conjugacy problem are constructed. Along the way, finitely generated, orbit undecidable, free ... -
The conjugacy problem in extensions of Thompson's group F
Burillo Puig, José; Matucci, Francesco; Ventura Capell, Enric (2016-10-01)
Article
Accés obertWe solve the twisted conjugacy problem on Thompson’s group F. We also exhibit orbit undecidable subgroups of Aut(F), and give a proof that Aut(F) and Aut+(F) are orbit decidable provided a certain conjecture on Thompson’s ... -
TOPOLOGIA
Ventura Capell, Enric (Universitat Politècnica de Catalunya, 2024-04-04)
Examen
Accés restringit a la comunitat UPC -
Twisted conjugacy in braid groups
Gonzalez Meneses, Juan; Ventura Capell, Enric (2014-01-01)
Article
Accés obertIn this note we solve the twisted conjugacy problem for braid groups, i.e., we propose an algorithm which, given two braids u,v is an element of B-n and an automorphism phi is an element of Aut(B-n), decides whether v = ... -
Twisted conjugacy problem for endomorphisms of metabelian groups
Ventura Capell, Enric; Romankov, Vitali (Springer, 2009-03-01)
Article
Accés restringit per política de l'editorialLet M be a finitely generated metabelian group explicitly presented in a variety A2 of all metabelian groups. An algorithm is constructed which, for every endomorphism ϕ ∈ End(M) identical modulo an Abelian normal subgroup ...