LIB "tst.lib";
tst_init();

option(redSB);             
ring R=0,(x,y),lp;            
ideal a1=x;                
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;       
ideal I1=quotient(I,h);
dim(std(I,h));

tst_status(1);$