Incidence Matrix Description of Intersecting p-brane Solutions
  An algebraic method for a general construction of intersecting p-brane solutions in diverse spacetime dimensions is discussed. An incidence matrix describing configurations of electric and magnetic fields is introduced. Intersecting p-branes are specified by solutions of a system of characteristic algebraic equations for the incidence matrix. This set of characteristic equations generalizes a single characteristic equation found before for a special "flower" ansatz. The characteristic equations admit solutions only for quantized values of scalar coupling parameters. A wide list of examples including solutions with regular horizons and non-zero entropy in D=11 and D=10 theories is presented. 
I.Ya.Aref'eva and O.A.Rytchkov