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。
Plans are worthless, but planning is everything.
系统辨识的挑战不仅在于拟合数据,还在于提取有意义且可推广的模型。
A good book should make you laugh, cry, and think.
读书最要紧的就是勤学好问,做人最要紧的就是实实在在而持之以恒。