On the augmented density of a spherical anisotropic dynamic system
  This paper presents a set of new conditions on the augmented density of a
spherical anisotropic system that is necessary for the underlying two-integral
phase-space distribution function to be non-negative. In particular, it is
shown that the partial derivatives of the Abel transformations of the augmented
density must be non-negative. Applied for the separable augmented densities,
this recovers the result of van Hese et al. (2011).
