Inequalities Between Size, Mass, Angular Momentum, and Charge for   Axisymmetric Bodies and the Formation of Trapped Surfaces
  We establish inequalities relating the size of a material body to its mass, angular momentum, and charge, within the context of axisymmetric initial data sets for the Einstein equations. These inequalities hold in general without the assumption of the maximal condition, and use a notion of size which is easily computable. Moreover, these results give rise to black hole existence criteria which are meaningful even in the time-symmetric case, and also include certain boundary effects. 
Marcus Khuri, Naqing Xie
gr-qc hep-th math.DG