很多不等式在展开以后形成如下的对称形式 sigma(s1^a1*s2^a2*...*sn^an)>=sigma(s1^b1*s2^b2*...*sn^bn) （当然 作为齐次不等式 a1+a2+....an=b1+b2+...bn 变量s1,s2,...sn非负） 其中sigma表示对称和（也就是说 一共n!项） 例如 sigma(x^3)=x^3y^0z^0+x^3z^0y^0+y^3x^0z^0+y^3z^0x^0+z^3x^0y^0+z^3y^0x^0=2

Six Sigma E book for Project Development and Technniques to implement

此书讲解了嵌入式系统的开发及测试过程，对嵌入式系统的测试介绍得很详细，很有参考价值。-Many enterprises regard system-level testing as the final piece of the development effort, rather than as a tool that should be integrated throughout the development process. As a consequence, test teams oft