Condiciones de contorno globales para el operador de Dirac
  Functional determinants for Dirac operators on manifolds with boundary are considered. Ellipticity of boundary value problems is discussed in terms of the Calderon projector.   The functional determinant for a Dirac operator on a bidimensional disk, in the presence of an Abelian gauge field, subject to global boundary conditions of the type introduced by Atiyah-Patodi-Singer, is evaluated. The relationship with the index theorem is also commented. 
H. Falomir