Singular

LIB "difform.lib";
ring R = 0,(x,y,z),ds;
diffAlgebra();
==> // The differential algebra Omega_R was constructed and the differential \
   forms dx, dy, dz are available.
/////////////////////////
// Degree computations //
/////////////////////////
deg(3*dx - x8*dx*dy);
==> 2
deg(3 + x8*dy);
==> 1
// When applying homog to a polynomial which is considered
// as a differential form, a type cast has to be done first
deg(x2-y);
==> 2
difform df = x2-y;
deg(df);
==> 0
kill Omega_R,df,dx,dy,dz;