ring r = 0,(x,y),ds;
ideal f = x,xy+y6+y9;
kbase(std(f));
ring s = 0,(x,y),dp;
ideal f = x,xy+y6+y9
;
kbase(std(f));
ideal f = x,xy+y6+y8+y9;
kbase(std(f));
setring r;
f = imap(s,f);
f;
kbase(std(f));
quit;