groebner基计算时，含有a1，a2,a3,...,an个自变量的非线性方程组问题化简问题

lhrman

a1*a2+2*a1*a3+a2*a3=0
4 u% F& J) V1 k, R0 z; M: @4 Ca1^2+a1*a2+a2^2+a2*a3+a3^2=1/4;
$ B. y& a8 N$ q8 Z8 e8 ]a1+a2+a3=1
用with（Groebner）；
/ ^9 ]8 P: D0 a2 m" m3 v然后输入
x := seq(a[k], k = 0 .. n)
7 M- m( \- N  d+ H2 L Basis(pl1, plex(x));
%;
8 z7 z  X1 J' j) _" Z- G9 ]# GError, too many levels of recursion
Basis(pl1, prod(x));
* @1 L$ Y8 i8 y1 f%;
& Q% a2 l7 ]2 ^  |% \7 ]) y! s$ y- IError, too many levels of recursion
然后显示错误求高手指点，我做的东西最好用a1,a2,...,an这样设置未知数我好编程