Conjugacy in Garside Groups III: Periodic braids

An element in Artin’s braid group Bn is said to be periodic if some power of it lies in the center of Bn. In this paper we prove that all previously known algorithms for solving the conjugacy search problem in Bn are exponential in the braid index n for the special case of periodic braids. We overco...

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Detalles Bibliográficos
Autores: Birman, Joan S., Gebhardt, Volker, González-Meneses López, Juan
Tipo de recurso: artículo
Estado:Versión enviada para evaluación y publicación
Fecha de publicación:2007
País:España
Institución:Universidad de Sevilla (US)
Repositorio:idUS. Depósito de Investigación de la Universidad de Sevilla
OAI Identifier:oai:idus.us.es:11441/42280
Acceso en línea:http://hdl.handle.net/11441/42280
https://doi.org/10.1016/j.jalgebra.2007.02.002
Access Level:acceso abierto
Palabra clave:Conjugacy problem
Braid groups
Periodic elements
Descripción
Sumario:An element in Artin’s braid group Bn is said to be periodic if some power of it lies in the center of Bn. In this paper we prove that all previously known algorithms for solving the conjugacy search problem in Bn are exponential in the braid index n for the special case of periodic braids. We overcome this difficulty by putting to work several known isomorphisms between Garside structures in the braid group Bn and other Garside groups. This allows us to obtain a polynomial solution to the original problem in the spirit of the previously known algorithms. This paper is the third in a series of papers by the same authors about the conjugacy problem in Garside groups. They have a unified goal: the development of a polynomial algorithm for the conjugacy decision and search problems in Bn, which generalizes to other Garside groups whenever possible. It is our hope that the methods introduced here will allow the generalization of the results in this paper to all Artin-Tits groups of spherical type.