Fermionic form and Betti numbers
  We state a conjectural relationship between the fermionic form (G. Hatayama, A. Kuniba, M. Okado, T. Takagi, Y. Yamada qa/9812022) and the Betti numbers of a Grassmannian over a preprojective algebra or, equivalently, of a lagrangian quiver variety. 
G. Lusztig