Singular

LIB "difform.lib";
ring R = 31,(x,y,z),dp;
diffAlgebra();
==> // The differential algebra Omega_R was constructed and the differential \
   forms dx, dy, dz are available.
////////////////////////////////////////////////////////////
// Construction of derivations from lists and polynomials //
////////////////////////////////////////////////////////////
list L; L[1] = list(dx,dz,dy); L[2] = list(x2,y-x,z);
derivation phi = L; phi;
==>  Omega_R^1 --> R
==>        dx |--> x2
==>        dy |--> z
==>        dz |--> -x+y
==> 
==> 
derivation psi = 3x2-12z; psi;
==>  Omega_R^1 --> R
==>        dx |--> 3x2-12z
==>        dy |--> 3x2-12z
==>        dz |--> 3x2-12z
==> 
==> 
kill Omega_R,dx,dy,dz,phi,psi;