当且仅当所有投资者都持有均值-方差有效的投资组合时,市场组合才是有效的。
In every word of a true writer, there is a piece of their soul, a fragment of their eternal quest for truth.
一个和谐的社会,不是争议的消失,而是公义的彰显。
A first sign of the beginning of understanding is the wish to die.
Aquaculture is agriculture's next frontier.