Workshop in Geometric Topology

Featured Speaker

The principal speaker for the workshop is Professor Peter Teichner of the University of California, San Diego. He will present a series of three one-hour lectures on "New obstructions for embedding 2-spheres into 4-manifolds".

ABSTRACT: In joint work with Rob Schneiderman, we have developed a new
obstruction theory for the embedding problem for 2-spheres in
4-manifolds. It is given in terms of the intersection theory of Whitney
towers, immersed in the 4-manifold, and it is related to Milnor
invariants and the Kontsevich integral in the easiest cases (where the
4-manifold is given by attaching 2-handles to a link in the 3-sphere).
As a consequence, we give an intersection theoretic explanation of the
Milnor invariants, and we relate them to the existence of embedded
gropes in the 4-ball.

In this sequence of talks, we shall give an outline of the theory,
explain the main results, and discuss the remaining open problems.
There are 3 papers, all joint with Rob Schneiderman (and one also joint
with Jim Conant) available on my homepage.

Lecture notes from the conference:

Lecture 1

Lecture 2

Lecture 3

Note these files are a little over 8MB. They may take a little while to load based on your connection speed.



		Featured Speaker The principal speaker for the workshop is Professor Peter Teichner of the University of California, San Diego. He will present a series of three one-hour lectures on "New obstructions for embedding 2-spheres into 4-manifolds". ABSTRACT: In joint work with Rob Schneiderman, we have developed a new obstruction theory for the embedding problem for 2-spheres in 4-manifolds. It is given in terms of the intersection theory of Whitney towers, immersed in the 4-manifold, and it is related to Milnor invariants and the Kontsevich integral in the easiest cases (where the 4-manifold is given by attaching 2-handles to a link in the 3-sphere). As a consequence, we give an intersection theoretic explanation of the Milnor invariants, and we relate them to the existence of embedded gropes in the 4-ball. In this sequence of talks, we shall give an outline of the theory, explain the main results, and discuss the remaining open problems. There are 3 papers, all joint with Rob Schneiderman (and one also joint with Jim Conant) available on my homepage. Lecture notes from the conference: Lecture 1 Lecture 2 Lecture 3 Note these files are a little over 8MB. They may take a little while to load based on your connection speed.