Métricas de Finsler esfericamente simétricas

We consider spherically symmetric Finsler metrics of Douglas type. We characterize such metrics by a differential equation and we obtain the general solution of this equation in terms of four arbitrary functions. For spherically symmetric Finsler metrics we show that the metrics of Berwald type coincide whit those of Landsberg type. We prove that the problem of classifying the spherically symmetric Douglas metrics whose S−curvature vanishes reduce to classifying the spherical symmetric metrics of Berwald or Landsberg type. We obtain the classification of such metrics. We include several examples and new classes of Douglas metrics. Key-words: Finsler. Spherically symmetric. Douglas Curvature. Landsberg Curvature. Berwald curvature.