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.
/////////////////
// Homogeneous //
/////////////////
homog(3*dx*dz - x8*dx*dy);
==> 1
homog(12x*dx + dy - (y4-y5)*dz);
==> 1
/////////////////////
// Not homogeneous //
/////////////////////
homog(3 + x8*dy);
==> 0
homog(x*dx+dy*dx);
==> 0
// When applying homog to a polynomial which is considered
// as a differential form, a type cast has to be done first
homog(3x-y2);
==> 0
difform df = 3x-y2;
homog(df);
==> 1
kill Omega_R,dx,dy,dz,df;