Geometry and Topology Seminar

In this talk we will show that a planar graph is the1-skeleton
of a Euclidean polyhedron inscribed in a hyperboloid if and only if it is
the 1-skeleton of a Euclidean polyhedron inscribed in a cylinder if and
only if it is the 1-skeleton of a Euclidean polyhedron inscribed in a
sphere and has a Hamiltonian cycle. This result follows from the
characterisation of ideal polyhedra in anti-de Sitter and half-pipe space,
a transitional geometry which is a limit of both hyperbolic and anti-de
Sitter geometry.
(This is joint work with J Danciger and J-M Schlenker.)