Existence of singularities in two-Kerr black holes
  We show that the angular momentum - area inequality 8\pi |J| =< A for weakly stable minimal surfaces would apply to (I^+)-regular many-Kerr solutions, if any existed. Hence we remove the undesirable hypothesis in the Hennig-Neugebauer proof of non-existence of well behaved two-component solutions. 
Piotr T. Chru\'sciel, Micha{\l} Eckstein, Luc Nguyen, Sebastian J.   Szybka
gr-qc