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
/ N& z; h7 y. `" g$ za1^2+a1*a2+a2^2+a2*a3+a3^2=1/4;
a1+a2+a3=1
3 x6 D" J; i/ F& t% u用with（Groebner）；
然后输入
# ~/ b' I8 k* u: ~% w% ~x := seq(a[k], k = 0 .. n)
Basis(pl1, plex(x));
+ X; N6 S# G6 K- A( P2 L; `/ C%;
1 c7 }# ~* H9 c1 k9 @; cError, too many levels of recursion
Basis(pl1, prod(x));
%;
) h* W! N9 N' V% YError, 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