//SINGULAR Example 3.6.10


LIB"normal.lib";



ring A = 0,(x,y,z),dp;
ideal I = y2-zx2;
LIB"surf.lib";
plot(I,"rot_x=1.45;rot_y=1.36;rot_z=4.5;");

list nor = normal (I);
def R = nor[1]; setring R;
norid; 
normap;