Sur la représentation conforme des surfaces de Riemann à bord et une caractérisation des courbes séparantes

Abstract

We present a simplified proof of a theorem due to Ahlfors: given a dividing real algebraic curve, it is always possible to find a morphism to the line such that the fibers over real points consist only of real points. Then in a second part, we show how our method - which is quite elementary, relying only on the use of Abel's theorem - even leads to a better bound on the degree of such a morphism than the one obtained by Ahlfors. © Swiss Mathematical Society.