 ring r=0,(x,y,z,a,b,c),dp;
ideal i=xy2z3a4b5+1,homog(xy2z3a4b5+1,c); i;
==> i[1]=xy2z3a4b5+1
==> i[2]=xy2z3a4b5+c15
ring r1=0,(a,b,x,y,z),lp;
ideal j=imap(r,i); j;
==> j[1]=a4b5xy2z3+1
==> j[2]=a4b5xy2z3
ring r2=(0,a,b),(x,y,z),ls;
ideal j=imap(r,i); j;
==> j[1]=1+(a4b5)*xy2z3
==> j[2]=(a4b5)*xy2z3
