Normal subgroups of the braid groups and the Dehornoy ordering

  • Date: 01/17/2007

Adam Clay (University of British Columbia)


University of British Columbia


The braid groups admit a left-ordering, known as the Dehornoy ordering,
which has come up under many guises in recent years. I will show that
normal subgroups interact with the Dehornoy ordering in such a way that
'nearly all' normal subgroups of the braid groups are densely ordered
with respect to this ordering. In particular, some popular normal
subgroups--such as the kernels of the Burau representations--can be
easily analyzed. This is joint work with Dale Rolfsen.

Other Information: 

Algebraic Topology Seminar 2007