|Title:||Security and insecurity in Riemannian manifolds|
|Seminar:||Center for Dynamics and Geometry Seminar|
|Speaker:||Keith Burns (Northwestern)|
|Two points in a Riemannian manifold form a secure configuration if all geodesics between them can be blocked by a finite number of points; otherwise they are insecure. I will survey the few known results.
In particular for compact manifolds with no conjugate points there is an alternative: either the manifold is flat and all configurations are secure or the manifold is not flat and all configurations are insecure.|