finding a fixed point for any lambda term.
+<a id=deriving-y></a>
## Deriving Y, a fixed point combinator ##
How shall we begin? Well, we need to find an argument to supply to
For those of you who like to watch ultra slow-mo movies of bullets
piercing apples, here's a stepwise computation of the application of a
recursive function. We'll use a function `sink`, which takes one
-argument. If the argument is boolean true (i.e., `\x y. x`), it
+argument. If the argument is boolean true (i.e., `\y n. y`), it
returns itself (a copy of `sink`); if the argument is boolean false
-(`\x y. y`), it returns `I`. That is, we want the following behavior:
+(`\y n. n`), it returns `I`. That is, we want the following behavior:
sink false <~~> I
sink true false <~~> I