//---Robot dell'esempio 1, [CLO, p. 299, 305-310]

ring r=(0,l3,l2,a,b),(c1,s1,c2,s2),dp;
option(redSB);
ideal id=l3*(c1*c2-s1*s2)+l2*c1-a,
l3*(c1*s2+c2*s1)+l2*s1-b,
c1^2+s1^2-1,c2^2+s2^2-1;
ideal j=std(id);
dim(j);
0
j;
j[1]=(2*l3*l2)*c2+(l3^2+l2^2-a^2-b^2)
j[2]=(2*l2*a^2+2*l2*b^2)*s1+(2*l3*l2*a)*s2+(l3^2*b-l2^2*b-a^2*b-b^3)
j[3]=(2*l2*a^2+2*l2*b^2)*c1+(-2*l3*l2*b)*s2+(l3^2*a-l2^2*a-a^3-a*b^2)
j[4]=(4*l3^2*l2^2)*s2^2+(l3^4-2*l3^2*l2^2-2*l3^2*a^2-2*l3^2*b^2+l2^4-2*l2^2*a^2-2*l2^2*b^2+a^4+2*a^2*b^2+b^4)
monitor("");