We first calculate the carry roll-down. This has two components: the cash-carry (i.e., the coupon payment) and the change in price.

问题如下：

Describe the different calculations that must be carried out in a P&L decomposition.

选项：

解释：

We first calculate the carry roll-down. This has two components: the cash-carry (i.e., the coupon payment) and the change in price. In calculating the carry roll-down, we assume that the spread remains unchanged. We then calculate the value of the bond for the actual change in the term structure assuming again that the spread remains unchanged. Finally, we calculate the effect on the bond price of the spread change.

题目问：描述在P&L分解中必须进行的不同的计算？

首先计算carry roll-down，这个包含两部分：cash-carry（比如说coupon的支付）和价格的改变。在计算carry roll-down时，我们假设spread不会发生变化。

然后，再假设spread不变的情况下，计算债券价格的实际变化。

最后，我们计算在spread变化的情况下，对债券价格的影响。