add names for omega and Omega

diff --git a/topics/week3_what_is_computation.mdwn b/topics/week3_what_is_computation.mdwn
index 0c9c5c5..b5c9d5b 100644 (file)
--- a/topics/week3_what_is_computation.mdwn
+++ b/topics/week3_what_is_computation.mdwn
@@ -135,11 +135,13 @@ pathological examples where the results do not align so well:
     (\x. x x) (\x. x x) ~~> (\x. x x) (\x. x x) ~~> (\x. x x) (\x. x x) ~~> ...
 
 In this example, reduction returns the exact same lambda term.  There
     (\x. x x) (\x. x x) ~~> (\x. x x) (\x. x x) ~~> (\x. x x) (\x. x x) ~~> ...
 
 In this example, reduction returns the exact same lambda term.  There

-is no simplification at all.
+is no simplification at all. (As we mentioned in class, the term `(\x. x x)` is often referred to in these discussions as (little) <b>&omega;</b>, or sometimes **M**; and its self-application <code>&omega; &omega;</code>, displayed above, is called (big) <b>&Omega;</b>.)
+
+Even worse, consider this term:

 
     (\x. x x x) (\x. x x x) ~~> (\x. x x x) (\x. x x x) (\x. x x x) ~~> ...
 
 
     (\x. x x x) (\x. x x x) ~~> (\x. x x x) (\x. x x x) (\x. x x x) ~~> ...
 

-Even worse, in this case, the "reduced" form is longer and more
+Here, the "reduced" form is longer and more

 complex by any reasonable measure.
 
 We may have to settle for the idea that a well-chosen reduction system
 complex by any reasonable measure.
 
 We may have to settle for the idea that a well-chosen reduction system