---
week3.mdwn | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/week3.mdwn b/week3.mdwn
index 26760eb0..c9e26757 100644
--- a/week3.mdwn
+++ b/week3.mdwn
@@ -146,7 +146,7 @@ But functions like the Ackermann function require us to develop a more general t
##How to do recursion with lower-case omega##
-...
+[TODO]
##Generalizing##
@@ -261,7 +261,9 @@ Two of the simplest:
```
Θ′ ≡ (\u f. f (\n. u u f n)) (\u f. f (\n. u u f n))
Y′ ≡ \f. (\u. f (\n. u u n)) (\u. f (\n. u u n))
```

-Θ′ has the advantage that `f (Θ′ f)`

really *reduces to* `Θ′ f`

. `f (Y′ f)`

is only convertible with `Y′ f`

; that is, there's a common formula they both reduce to. For most purposes, though, either will do.
+Θ′ has the advantage that `f (Θ′ f)`

really *reduces to* `Θ′ f`

.
+
+`f (Y′ f)`

is only convertible with `Y′ f`

; that is, there's a common formula they both reduce to. For most purposes, though, either will do.
You may notice that both of these formulas have eta-redexes inside them: why can't we simplify the two `\n. u u f n` inside `Θ′`

to just `u u f`? And similarly for `Y′`

?
--
2.11.0