h` computed the fixed point. In the schema here, `h1` had better be a
function which, when you give it suitable arguments, computes the
first fixed point `X1` (likewise for `h2` wrt the second fixed point
-`X2`). Then we can arrange for our definition to return the desired
+`X2`).
+
+Then we can arrange for our definition to return the desired
fixed point like this:
let Y1 = \pe po . (\h1 h2 . pe (h1 [blah])(h2 [blah]))
(\h1 h2 . ...)
The term in the middle line is going in for `h1`, so it had better
-be the kind of thing which, when you give it suitable arguments,
+also be the kind of thing which, when you give it suitable arguments,
computes a fixed point for `pe`:
let Y1 = \pe po . (\h1 h2 . pe (h1 [blah]) (h2 [blah]))
All we need to do is figure out what the arguments to `h1` and `h2`
ought to be. Final guess: in the original, `h` took one argument (a
-copy of itself), so once again, we'll need two arguments. Here's
+copy of itself), so once again, here we'll need two arguments. Here's
where the mutual recursion comes in: the two arguments to `h1` are a
copy of itself, and a copy of `h2` (symmetrically for `h2`). So the
complete definition is