author: | Elisha Falbel and Pierre-Vincent Koseleff |
title: | The Number of Sides of a Parallelogram |
keywords: | Lie algebras, free group, Magnus group, lower central series, Lyndon basis |
abstract: | We define parallelograms of base a and b in a group. They appear as minimal relators in a presentation of a subgroup with
generators a and b.
In a Lie group they are realized as closed polygonal lines, with sides
being orbits of left-invariant vector fields. We estimate the number of
sides of parallelograms in a free nilpotent group and point out a
relation to the rank of rational series.
|
reference: |
Elisha Falbel and Pierre-Vincent Koseleff (1999),
The Number of Sides of a Parallelogram,
Discrete Mathematics and Theoretical Computer Science 3, pp. 33-42 |
ps.gz-source: | dm030201.ps.gz (34 KB) |
ps-source: | dm030201.ps (110 KB) |
pdf-source: | dm030201.pdf (74 KB) |