Mixed Discriminants
  The mixed discriminant of n Laurent polynomials in n variables is the irreducible polynomial in the coefficients which vanishes whenever two of the roots coincide. The Cayley trick expresses the mixed discriminant as an A-discriminant. We show that the degree of the mixed discriminant is a piecewise linear function in the Plucker coordinates of a mixed Grassmannian. An explicit degree formula is given for the case of plane curves. 
Eduardo Cattani, Maria Angelica Cueto, Alicia Dickenstein, Sandra Di   Rocco, Bernd Sturmfels
math.AG cs.SC math.CO