Normal rulings of Legendrian links

Geometry Topology Student Seminar
Wednesday, February 8, 2017 - 14:05
1 hour (actually 50 minutes)
Skiles 006
Georgia Tech
Normal rulings are decompositions of a projection of a Legendrian knot or link. Not every link has a normal ruling, so existence of a normal ruling gives a Legendrian link invariant. However, one can use the normal rulings of a link to define the ruling polynomial of a link, which is a more useful Legendrian knot invariant. In this talk, we will discuss normal rulings of Legendrian links in various manifolds and prove that the ruling polynomial is a Legendrian link invariant.