Speaker: Christine Uhl (University of North Texas)

Title: Euler Number for Orbifolds

Abstract: There are 17 symmetry patterns in the plane, examples of which have appeared in art and design throughout history. Starting with a pattern in the plane, we identify symmetric points to obtain a geometric object known as an orbifold. We will examine several symmetry patterns, determine the corresponding orbifolds, and explicitly compute their Euler numbers. We will discuss mirrors, cone points, cross-caps and gyration points.