Discrete Geometry Group

Stephan Hell

Former Address

Technische Universität Berlin
Fakultät II: Institut für Mathematik, MA 6-2,
Straße des 17. Juni 136
10623 Berlin
Germany

Room:	MA 623
Phone:	+49-30-314-25758
Fax:	+49-30-314-21269
Email:

Interests/Research

• Knot Theory
• Algebraic Topology
• Combinatorics
• Computational Geometry

Publications and preprints

• Tverberg's theorem with constraints,
  J. Combinatorial Theory, Ser. A, 115 (2008), 1402-1416.
• On the number of Birch partitions ,
  Discrete & Computational Geometry, 40 (2008), 586-594.
• Tverberg-type theorems and the Fractional Helly property,
  PhD thesis, 2006, published online.
• On the number of Tverberg partitions in the prime power case, ( ps , pdf ),
  European Journal of Combinatorics, 28 (2007), 347-355.
• On a topological fractional Helly theorem ( ps , pdf ),
  Preprint, 11 pages, 2005. (arXiv.math.CO/0506399)
• TverbergTest, a Java program for checking the topological Tverberg theorem and Sierksma's conjecture in dimension 2 and 3, test maps are defined through random points, files available on request.
• Die Nenner des Kontsevich-Integrals und ein spezieller Drinfeld-Assoziator ( ps , pdf ),
  Diploma thesis (in knot theory), 95 pages, FU Berlin, 2003, Supervisor Prof. Dr. Elmar Vogt,
• String Matching Algorithmen ( ps , pdf ),
  (Old) Notes, 48 pages, FU Berlin, 2000, Course of Dr. Frank Hoffmann.

Links

• A collection of links for literature search (in German).
• As part of my PhD program, I stayed the winter semester '04/'05 with Prof. Jiří Matoušek at the Department of Applied Mathematics of Charles University, Prague. The institute is a very welcoming place with a large number of active people. The city is a very nice place with lots of things to discover.
• During my studies, I spent the academic year '98/'99 at Université Joseph Fourier in Grenoble, France. It is a good place for studying knot theory, for skiing, and for meeting a lovely french girl.
  
• I'm an active member of the running team FU Mathe Team of the Mathematics Department at Freie Universität Berlin.