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Mostrando ítems 21-30 de 32
Artículo
Conjugacy in Garside Groups III: Periodic braids
(Elsevier, 2007-10-15)
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 ...
Artículo
On the structure of the centralizer of a braid
(Elsevier, 2004)
The mixed braid groups are the subgroups of Artin braid groups whose elements preserve a given partition of the base points. We prove that the centralizer of any braid can be expressed in terms of semidirect and ...
Artículo
Generating random braids
(Elsevier, 2013-01)
We present an algorithm to generate positive braids of a given length as words in Artin generators with a uniform probability. The complexity of this algorithm is polynomial in the number of strands and in the length of ...
Artículo
On the singular braid monoid of an orientable surface
(American Mathematical Society, 2004)
In this paper we show that the singular braid monoid of an orientable surface can be embedded in a group. The proof is purely topological, making no use of the monoid presentation.
Artículo
Geometric embeddings of braid groups do not merge conjugacy classes
(Sociedad Matemática Mexicana, 2014-10)
An embedding of the m-times punctured disc into the n-times punctured disc, for n > m, yields an embedding of the braid group on m strands Bm into the braid group on n strands Bn, called a geometric embedding. The main ...
Artículo
Presentations for the monoids of singular braids on closed surfaces
(Taylor & Francis, 2002)
We give presentations, in terms of generators and relations, for the monoids SBn(M) of singular braids on closed surfaces. The proof of the validity of these presentations can also be applied to verify, in a new way, the ...
Artículo
On the centralizer of generic braids
(De Gruyter, 2018-11)
We study the centralizer of a braid from the point of view of Garside theory, showing that generically a minimal set of generators can be computed very efficiently, as the ultra summit set of a generic braid has a very ...
Artículo
A geometric characterization of the upper bound for the span of the Jones polynomial
(World Scientific, 2011-07)
Let D be a link diagram with n crossings, sA and sB its extreme states and |sAD| (resp. |sBD|) the number of simple closed curves that appear when smoothing D according to sA (resp. sB). We give a general formula for the ...
Artículo
Reducible braids and Garside theory
(Geometry & Topology Publications, 2011)
We show that reducible braids which are, in a Garside-theoretical sense, as simple as possible within their conjugacy class, are also as simple as possible in a geometric sense. More precisely, if a braid belongs to a ...
Artículo
Polynomial braid combing
(Oxford University Press, 2018)
We prove that, for n ≥ 3, the minimal dimension of a model of the classifying space of the braid group Bn, and of the pure braid group Pn, with respect to the family of virtually cyclic groups is n.