Universiteit Leiden Mathematisch Instituut
Geometry Seminar

Wednesday, 27 September 2006, 16:00 - 17:00, room 401.

Oleg Karpenkov: Lattice trigonometry

Abstract:

In this talk we discuss some properties of lattice trigonometric functions of lattice angles in lattice geometry. We introduce a necessary and sufficient condition for three angles to be the angles of some lattice triangle in terms of lattice tangents. This condition is a version of the Euclidean condition: three angles are the angles of some triangle iff their sum equals pi. We say also a few words about connections with theory of complex projective toric varieties.