Speaker: Handan Yildirim（Istanbul University）

Time: 16:00-17:00, July 19

Venue: 数学中心研讨室（至善楼602）

Title: Legendrian dual surfaces of a spacelike curve in the 3-dimensional lightcone

Abstract:

   In this talk, we discuss Legendrian dual surfaces, lying in the 3-dimensional pseudo-(hyper)spheres of various radii in Lorentz-Minkowski 4-space, of a spacelike curve in the 3-dimensional lightcone. We point out that these surfaces are constructed by the extended Legendrian dualities between the 3-dimensional lightcone and these 3-dimensional pseudo-spheres. Moreover, we investigate the singularities of these surfaces and show the dualities of the singularities of a certain class of such a surface in the 3-dimensional lightcone. Furthermore, we deal with the singularities of all of these surfaces when they are non-flat. This is based on a joint work with Kentaro Saji.