Singular

LIB "difform.lib";
ring R = 0,(x,y,z),ds;
diffAlgebra();
==> // The differential algebra Omega_R was constructed and the differential \
   forms dDx, dDy, dDz, dx, dy, dz are available.
//////////////////////////
// Application of Print //
//////////////////////////
difform df = 3*x*dx - y*dx*dy + 12*dx*dy*dz - dz*dy + 3 + 12*x*dx;
df;
==> 3+15x*dx+(-y)*dx*dy+dy*dz+12*dx*dy*dz
==> 
kill Omega_R,df,dx,dy,dz;