#
Monday Lecture and Colloquium

**Monday, June 16, 2014**

Technische Universität Berlin

Fakultät II, Institut für Mathematik

Str. des 17. Juni 136

10623 Berlin

room MA 041

** Lecture - 14:15**

### Fedor Fomin -
University of Bergen

### Minimal separators

*Abstract:*

For vertices x,y of a graph G, vertex subset S is a minimal x,y-separator if S separates x and y (x and y are in different connected components of G-S) and S is minimal (no proper subset of S separates x and y). Minimal separators are a handy tool to study graph triangulations, in particular the treewidth and the fill-in of graphs. In this talk we overview several applications of minimal separators in parameterized and exact exponential algorithms. We also discuss algorithms enumerating minimal separators.

** Colloquium - 16:00**

### Maryna Viazovska -
Hausdorff Center for Mathematics, Bonn

### Minimal energy problems and t-designs on a sphere

*Abstract:*

In this talk we will discuss the interrelation between classical optimization problems on spheres S^d such as minimal equal-weight quadratures (spherical designs) and minimal energy problems. In a joint work with A. Bondarenko and D. Radchenko we have proved the existence of certain configurations in S^d which are spherical t-designs with asymptotically minimal number of points and which simultaneously have asymptotically the best separation property. These configurations also provide approximate solutions for a wide class of minimal problems.

Letzte Aktualisierung:
11.06.2014