Papers by Andreas Balser

• Convex rank 1 subsets of Euclidean buildings (of type A_2), Geometriae Dedicata, 2008, Volume 131 (1), pp. 123-158; Arxiv: math.MG/0610947
  This article contains the main result of my PhD thesis.
• Building-like spaces, with Alexander Lytchak,
  Journal of Mathematics of Kyoto University, 2007, Volume 46(4), pp. 789-804; Arxiv: math.MG/0410437.
  In this paper, we study convex subsets of buildings, discuss some structural features and derive several characterizations of buildings.
• Polygons with prescribed Gauss map in Hadamard spaces and Euclidean buildings,
  Canadian Mathematical Bulletin, 2006, Voume 49(3), pp. 321-336, Arxiv: math.MG/0412050.
  In this article, we classify the conditions under which configurations on its boundary yield a polygon in the building X. For Hadamard spaces, sufficient conditions are given.
• Centers of convex subsets of buildings, with Alexander Lytchak;
  Annals of Global Analysis and Geometry, Sept. 2005, Volume 28(2), pp. 201-209; Arxiv: math.MG/0410440.
  Here, it is shown that two dimensional convex subsets of spherical buildings are either buildings or have a center.
• Towards a Classification of CMC-1 Trinoids in hyperbolic space via conjugate surfaces,
  Kobe Journal of Mathematics, 2006, Volume 23, pp. 51-63; Arxiv: math.DG/0310397.
  This paper merges the results of Benoit Daniel and my diploma thesis, and discusses to which extent one can use conjugate minimal surfaces for a classification of CMC-1 trinoids in hyperbolic space.

• PhD thesis "On the interplay between the Tits boundary and the interior of Hadamard spaces" diss.pdf
  My thesis comprises "Convex rank 1 subsets ...", "Polygons ...", and some results on convex rank 1 subsets of SL(3)/SO(3).
• My diploma thesis (March 03): On Trinoids and Minimal Disks bounded by Lines (600 KB).

• Summer School on Commutative Formal Groups (Sept. 03) Together with Kristian Bruening and Fridolin Roth, I presented connections between formal group theory and topology. My talk covered BP-Homology. The handout also contains a section about Landweber's classification of cohomology operations on MU, which I didn't present in the talk. The handout is in German.
  Kristian Bruening wrote a handout about his introductory talk, too. The talk covered (among other topics) generalised homology theories, spectra, and how one obtains a formal group law from a generalised homology theory. If you are interested in the handout, feel free to contact him under "kbruenin AT mathematik . uni - bielefeld . de".
• Seminar: "Ausgewählte Kapitel der Gruppen- und Darstellungstheorie" (Prof. Neeb, TU Darmstadt, WS 01/02, in German and in the order in which the talks were given; not all given talks are listed)
  • Grundlagen über Mannigfaltigkeiten und Integration auf Mannigfaltigkeiten (Christoph Wockel) contains the first part of an introductory chapter on manifolds.
  • Homogene Räume und Bahnräume von Lie-Gruppen (Christoph Müller), contains the second part of the introductory chapter mentioned above and covers homogenous spaces. Some of this material is used in my text.
  • Transformationsgruppen (my seminar topic), discusses the action of a Lie group on a manifold (and the connections to its "differential", a so-called infintesimal transformation group).
  • Integration auf Mannigfaltigkeiten (Christoph Wockel) A brief introduction to the theory of integration on manifolds.

• Primzahlnachweis mit Hilfe elliptischer Kurven: Handout for a talk in a seminar on elliptic curves: This talk was about ECPP (the primality proving algorithm that uses elliptic curves); includes some material on pseudoprime-tests. (In german) (2000)
• Pseudoprimes and elliptic curve primality proving (ECPP): Handout for a talk in the student seminar at tulane. Includes a brief introduction to elliptic curves; the coverage of ECPP is less detailed than in the text above. (2001)
• A short introduction to topological vector spaces: Handout for a series of talks in the analysis 2 lecture at Tulane. Heavily based on Rudin's book "Functional analysis". (2001)