New Connections Between 4D and 5D Black Holes
  A simple equality is proposed between the BPS partition function of a general 4D IIA Calabi-Yau black hole and that of a 5D spinning M-theory Calabi-Yau black hole. Combining with recent results then leads to a new relation between the 5D spinning BPS black hole partition function and the square of the N=2 topological string partition function. 
D. Gaiotto, A. Strominger, X. Yin