StableIdeal(L: LIST of power-products): IDEAL
/**/ use R ::= QQ[x,y,z]; /**/ L := [x*z^4, y^3]; /**/ StableIdeal(L); ideal(x^2*z^3, x*y*z^3, x*z^4, x^3, x^2*y, x*y^2, y^3)