Criteria for singularities for mappings from two--manifold to the plane.   The number and signs of cusps
  Let M be a two--dimensional complete intersection. We show how to check whether a mapping f: M-->R^2 is 1-generic with only folds and cusps as singularities. In this case we give an effective method to count the number of positive and negative cusps of a polynomial f, using the signatures of some quadratic forms. 
Iwona Krzy\.zanowska and Aleksandra Nowel
math.AG