Singular

LIB "difform.lib";
ring R = 0,(x,y,z),lp;
diffAlgebra();
==> // The differential algebra Omega_R was constructed and the differential \
   forms dDx, dDy, dDz, dx, dy, dz are available.
/////////////////////////////////////////////////
// Universal derivation applied to polynomials //
/////////////////////////////////////////////////
difformUnivDer(3x);
==> 3*dx
==> 
difformUnivDer(xyz+x2y2z2);
==> (2xy2z2+yz)*dx+(2x2yz2+xz)*dy+(2x2y2z+xy)*dz
==> 
difformUnivDer(x+y+z);
==> dx+dy+dz
==> 
kill Omega_R,dx,dy,dz;