Einladung zum FACHBEREICHSKOLLOQUIUM des
FB Mathematik und Informatik der FU Berlin:
Es spricht

        Prof. Dr. Gaiane Panina (St. Petersburg)

zum Thema

               Pseudotriangulations

Zeit: Do., 26.10.06, 17 Uhr c.t.
Ort: Hörsaal Informatik, Takustraße 9, 14195 Berlin

Tee, wie immer, ab 16:45,
jedoch diesmal in Raum 137, FU-Informatik, Takustraße 9, 1. Stock

ABSTRACT:
We show that the following two (quite different!) problems have one and the
same combinatorial background.

1. Carpenter's rule problem.
   Can any carpenter's ruler (a closed planar non-crossing closed
   broken line) be straightened in the plane avoiding self-crossing?
2. A.D. Alexandrov's problem.
   Given a smooth convex 3D-body K and a constant C which separates
   the principal curvature radii of K (i.e. R1 <= C <= R2 everywhere),
   is K necessarily a ball?

The talk is based on papers by R. Connelly,  R. Haas, Y. Martinez-Maure,
D. Orden, G. Rote, F. Santos, B. Servatius, H. Servatius,  I. Streinu,
W. Whiteley, the speaker and others.