In the first, `P` has become `int` and `Q` has become `bool`. (The boxed type <code><u>Q</u></code> is <code><u>bool</u></code>).
Note that the left-hand schema `P` is permitted to itself be a boxed
-type. That is, if `α list` is our box type, and `P` is to boxed type
+type. That is, if `α list` is our box type, and `P` is the boxed type
`int list`, we can write the boxed type that has `P` as its left-hand
side as