# Harald Bohr Lecture: Etienne Ghys (ENS Lyon)

Title: The topology of a curve in the neighborhood of a singular point

Speaker: Etienne Ghys (Directeur de recherche CNRS, ENS Lyon)

Abstract: I would like to start with a clever (and elementary) observation of M. Kontsevich. When we draw the graphs of four real polynomials in one variable intersecting in some point, some local qualitative pictures turn out to be impossible. I will then generalize to any number of polynomials and then to singularities of real algebraic curves. Some interesting algebraic structures appear and open questions arise…