• Modelos minimales de la recta hiperreal 

      Alvarado Jiménez, William (2009-02-18)
      A new proof of the existence of minimal models of the hiperreal line is obtained in terms of a combinatorial property of Ramsey ultrafilters over a countable set.
    • Puntos fijos hiperbólicos de un difeomorfismo local del plano 

      Alvarado Jiménez, William (2009-02-18)
      An extension of J. Palis’ lambda-lemma is obtained for one case of non-transversal intersection of the stable and unstable manifolds of an hyperbolic fixed point of a C2 local diffeomorphism of R2.