 ring R;
poly f = x2yz + xy3z + xyz5;
ideal i = jacob(f); i;
==> i[1]=yz5+y3z+2xyz
==> i[2]=xz5+3xy2z+x2z
==> i[3]=5xyz4+xy3+x2y
matrix m = jacob(i);
print(m);
==> 2yz, z5+3y2z+2xz, 5yz4+y3+2xy,
==> z5+3y2z+2xz,6xyz, 5xz4+3xy2+x2,
==> 5yz4+y3+2xy,5xz4+3xy2+x2,20xyz3
print(jacob(m));
==> 0, 2z, 2y, 2z, 6yz,5z4+3y2+2x,2y, 5z4+3y2+2x,\
20yz3,
==> 2z,6yz, 5z4+3y2+2x,6yz, 6xz,6xy, 5z4+3y2+2x,6xy, \
20xz3,
==> 2y,5z4+3y2+2x,20yz3, 5z4+3y2+2x,6xy,20xz3, 20yz3, 20xz3, \
60xyz2
