SUSSEX/SOUTHAMPTON/LONDON TOPOLOGY MEETING

Friday 4 June 1999

Location: Pevensey Building, room 1A1

TALKS

2.00 Brian Sanderson (Warwick) "Knot invariants from the rack space."

ABSTRACT: Knots have characteristic classes in the homology of the
rack space and the action rack space. Applications to distinguishing
right and left trefoils and `right' and `left' twist spun trefoils
will be given.
 
3.00 Dale Rolfsen (UBC)  "Ordered groups, local indicability and braids."

ABSTRACT: Locally indicable groups are right-orderable, but not
conversely -- witness the braid groups B_n for n>4.  However, if a
right-ordering has a certain symmetry property, due to Conrad, the
converse statement holds.  Moreover, this property holds if it
virtually holds. It was recently discovered that the PURE braid
groups enjoy an ordering which is invariant under multiplication on
both the left and right.  As an application of the above, we show
that such an ordering is necessarily incompatible with any 1-sided
ordering of B_n, n>4.  This is joint work with Akbar Rhemtulla.

4.00 Tea
4.30 Graduate Students Research Announcements
5.00 Ray Lickorish (Cambridge) "Genus 2 mutations of knots"

6.30 The Royal Oak, Station St, Lewes,
7.00 Light of Bengal, Landsdowne Place, Lewes