A better length function for Artin's braid groups

نویسندگان

  • Martin Hock
  • Boaz Tsaban
چکیده

Having a good length function on a group is the main ingredient in a recent combined memory/length approach to solving random equations in that group. Currently, the groups of greatest interest in this respect are Artin’s braid groups. We demonstrate, by a series of experiments, that a length function based on the Birman-Ko-Lee presentation of the braid group is substantially better than the corresponding function based on the Artin presentation.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Representing Braids by Automorphisms

Based on a normal form for braid group elements suggested by Dehornoy, we prove several representations of braid groups by automorphisms of a free group to be faithful. This includes a simple proof of the standard Artin's representation being faithful.

متن کامل

The Set of Minimal Braids is co-NP-Complete

Braids ñàï Üå represented as two-dimenSional diagrams showing the crossings of strings or as words over the generators of à braid group. À minimal braid is îïå with the fewest crossings (or the shortest words) among all possible repre~entations topologically equivalent to that braid. ÒÜå main result of this paper is that the set of minimal braids is co-NP-complete. Algorithmic problems in braid...

متن کامل

Complete simultaneous conjugacy invariants in Artin's braid groups

We provide the first effectively computable, modulo a mild conjecture, complete invariant for simultaneous conjugacy in Garside groups. This invariant generalizes the notion of super summit set of a conjugacy class, and provides a solution of the simultaneous conjugacy problem in Garside groups, of complexity a small degree polynomial in the sizes of the invariant and the input parameters. Comp...

متن کامل

On Artin's Braid Group and Polyconvexity in the Calculus of Variations

Let Ω ⊂ 2 be a bounded Lipschitz domain and let F : Ω× 2×2 + −→ be a Carathèodory integrand such that F (x, ·) is polyconvex for L2-a.e. x ∈ Ω. Moreover assume that F is bounded from below and satisfies the condition F (x, ξ) ↘ ∞ as det ξ ↘ 0 for L2-a.e. x ∈ Ω. The paper describes the effect of domain topology on the existence and multiplicity of strong local minimizers of the functional [u] := ∫

متن کامل

Braid Group Cohomologies and Algorithm Complexity

Smale's method is of very general character: it provides an estimate of the topological complexity of any nonlinear ill-posed problem by means of a topological characteristic of the corresponding fibration, namely, its genus introduced and studied by Shvarts in[7] (and rediscovered in [8]). In the case of the problem on polynomial roots, an estimate of the genus [of which the inequality (i) is ...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • CoRR

دوره abs/math/0611918  شماره 

صفحات  -

تاریخ انتشار 2006