为什么风险系数是1.4就需要做空

A stock with an expected return of 9.0%：不应该表示E(rp)吗为什么题目中表示成了R（f）

factor up代表的是什，卡面的代笔表的是什么

F&F have observed: firms with high ratios of book-to-market value are more likely to be in financial distress and that small stocks may be more sensitive to changes in business conditions. 如何理解这句好

 The differences between CAPM and APT:  CAPM is a one-factor model and APT is a multi-factor model.  CAPM is a special case of APT.  APT is often used to decompose the factors' respective contributions to the expected return.中最后APT is often used to decompose the factors' respective contributions to the expected return.如何理解这句话

each by a relatively small dollar amount如何理解

There are no arbitrage opportunities among well-diversified portfolios.中如何理解well-diversified portfolios

老师好，视频1:43:40的tail loss用insurance来覆盖，和覆盖EL的保费有什么区别？谢谢！

为什么是次方而不是直接乘

如何理解U效用，全程是什么？