画线这句话表达什么意思

两种组合的VAR 计算方式有什么区别，VAR(bond)和VAR(int)都怎么求

这个债券的risk 就是VAR是如何求出来的

为什么对手方是oil corp时，PD上升，则oil price会下降呢？

k-max(k-v,0)是怎么得出来的？

这个题能不能详细讲一下，选项b是什么意思

怎么理解The sum of the variances of the PCs equals the sum of the variances of the individual rates 这句话？

老师信用风险122页这一段Another difficulty with the Merton model is that default is too ​predictable. Remember that to obtain prices of debt in that ​model, we make the Black Scholes assumptions. We know that ​with these assumptions firm value cannot jump. As a result, ​default cannot occur unless firm value is infinitesimally close to ​the point where default occurs. In the real world, default is often ​more surprising. For instance, a run on a bank could make its ​equity worthless even though before the run its equity value was ​not close to zero.没太看懂能讲一下吗？谢谢

老师书上第121页，One way ​Panel B ​Debt value ​.... 42 ​40 ​10 ​Maturity ​-I ​0.2 ​is to compute the delta-VaR by transforming the risky ​debt into a portfolio of the risk-free bond and of the ​debtor's equity if we are computing a VaR for a short ​period of time. A second way is to compute the Monte ​Carlo VaR by simulating equity returns and valuing ​0.1 ​Interest rate ​volatility ​the debt for these equity returns. If the firm has other ​assets, we must consider the correlations among the ​asset returns.这段说计算var 其中一种把deltavar 看作无风险债务和债权人的权益来计算，第二种通过模拟股票回报率来计算，就没看懂，能解释一下吗

老师你好 这里的holding period是不是应该指的是horizon呢？这里周老师和梁老师在高效基础网课里讲的好像不太一样呢