Orateur
Jean Chartier
(LAMA)
Description
Simple closed geodesics on Riemannian spheres have been the subject of many incomplete existence proofs throughout the 20th century, since Birkhoff's first paper in 1908. One stumbling block is preserving the simplicity of the curves by using shortening flows. In 1994, Hass and Scott described a new flow for shortening curves: the disc flow, which solves the simplicity issue, but brings other difficulties. We present an adaptation of this flow in a discrete setting, as well as a new proof of Birkhoff's theorem.
