摘要
An optimal investment strategy is extremely worth discussing and studying in our actual investment activities, not only for individual investors and companies but also for governments and all other kinds of investors. And there is no doubt that we cannot find the only way and meet the needs of every investor. But if we can get an authoritative ranking according to the needs of investors, we can find the different best investment portfolio for different investors who have different view of risk theoretically and practically. From a typical case. all about these problems is what I will discuss in this article.