13.0.1 `poly_degree'
--------------------

poly_degree(F)
     :  It returns the degree of F with respect to the given weight
     vector.

poly_degree(F | WEIGHT=key0,V=key1)
     : This function allows optional variables   WEIGHT, V

   Description:

     The weight is given by the optional variable weight w.   It returns


   Example:
      poly_degree(x^2+y^2-4 |weight=[100,1],v=[x,y]);

