//SINGULAR Example4.4.10 //========================== we need============================== option(redSB); //to obtain a reduced normal form ring R=0,(x,y),lp; ideal a1=x; //preparation of the example ideal a2=y2+2y+1,x-1; ideal a3=y2-2y+1,x-1; ideal I=intersect(a1,a2,a3); poly h=y4-2y2+1; //the lcm of the leading coefficients ideal I1=quotient(I,h); //================================================================ ideal I2=quotient(I,I1); I2;