KTH/SU Mathematics Colloquium

06-03-29

Mattias Dahl, KTH

Surgery and Geometry

The procedure of surgery is one of the most powerful tools in the study of smooth manifolds, leading to results such as the solution to the Poincare conjecture in $dim \geq 5$ and the classification of compact manifolds of a given homotopy type.

Rather surprisingly surgery can in certain cases be used to study manifolds with additional geometric structure. The main example of this is the case of manifolds with Riemannian metrics of positive scalar curvature. I will discuss this and some other cases where surgery can be applied to geometric and analytic problems.