Abstract: Smooth surfaces are often approximated by triangulations. When the triangles are flat the curvature of the original surface becomes reflected in angle defects at vertices: the angles of the triangles meeting at a vertex do not sum to 2π, and the difference is called the deficit angle. The deficit angle has been proposed as a measure of the gaussian curvature at vertices and I will give a rigorous interpretation and proof of this intuition. (The talk will be in English.)

Lecturer: Snorre Christiansen