xmuwym2 发表于 2013-12-1 22:10 
我列举一个:
EMH里面不要求投资者是同质的,异质投资者是ok的,只要人数够多就行。
Markowitz投资组合 ...
这是作者在1952年的论文里的内容
We next consider the rule thatthe investor does (or should) consider expected return a desirable thing and variance of re- turn an undesirable thing. This rule has many sound points,both as a maxim for, and hypothesis about, investment behavior.
开始部分我的理解是推导这些过程的假设的是理性的投资者遵循一些基本的偏好,而并未要求所有的投资者是同质的,或者说如果市场有投资者不是这样的,就无法得出文中的结论。这个假设只是说明有这样偏好的投资者会如此行为。
有一个佐证是:
To use the E-V rule in the selection of securities we must have pro- ceduresfor finding reasonable pi and aij. These procedures, I believe, should combine statistical techniques and the judgment of practicalmen. My feeling is that the statistical computations should be used to arrive ata tentative set of pi and aij. Judgment should then be used in increasing or decreasingsome of these pi and uij on the basis of factors or nuances not taken intoaccount by the formal computations. Using this revised set of pi knd uij, the setof efficient E, V combina- tions could be computed, the investor couldselect the combination he preferred, and the portfolio which gave rise to this E, V combination could be found.
文中最后部分的一个说明,作者都认为应该包含practical men的个人判断了,自然也就说明并未要求所有的投资者是同质的。
我是这么理解的,而且我看推导过程没有哪说所有投资者的效用函数如何如何,之前上课老师没讲这篇原文,我自己读的,我认为我的理解是没错的,也是符合作者本意的,大家可以共同评价一下。