WHEN: 21.05.15 at 14:15
WHERE: Seminar Room, Arnimallee 2, FU Berlin

Speaker: Hao Chen (FU Berlin)

Dressing code for the sphere - scribability problems of polytopes

We will study various scribability problems, including the classical one studied by Steinitz and Schulte, the weak one proposed by Grünbaum-Shephard and Schulte, and the new (i, j)-scribability which requires faces to cut or avoid the sphere instead of being tangent.  We obtain new results for each of these problems.  In particular, classical scribabilities are fully answered for stacked and cyclic polytopes; and the loose end left by Schulte on weak scribability is tied up.  As for the new (i, j)-scribability, we find counter examples in most cases, but leave two cases open.  This is a joint work with A. Padrol.