13.0.5 `poly_grobner_basis'
---------------------------

poly_grobner_basis(I)
     :  It returns the Grobner basis of I.

poly_grobner_basis(I | ORDER=key0,V=key1)
     : This function allows optional variables   ORDER, V

   Description:

     The optional variable v is a list of variables which defines the
     ring  of polynomials.


   Example:
      A = poly_grobner_basis([x^2+y^2-4,x*y-1]|order=2,v=[y,x]);

