X-Git-Url: http://lambda.jimpryor.net/git/gitweb.cgi?p=lambda.git;a=blobdiff_plain;f=hints%2Fassignment_4_hint_3_alternate_1.mdwn;h=99a4202b59946a7da55a8cff6cef5837460dec3c;hp=dd55e052ec797db0bb714575a94133c76cf5a304;hb=8c28339b991f2d4f0940d295bf4d265a00751b05;hpb=1f4f3108441cfd887eb5c9e6ee53a651a80166ea

diff --git a/hints/assignment_4_hint_3_alternate_1.mdwn b/hints/assignment_4_hint_3_alternate_1.mdwn
index dd55e052..99a4202b 100644
--- a/hints/assignment_4_hint_3_alternate_1.mdwn
+++ b/hints/assignment_4_hint_3_alternate_1.mdwn
@@ -11,13 +11,23 @@ Alternate strategy for Y1, Y2
 
 	is implemented using regular, non-mutual recursion, like this (`u` is a variable not occurring free in `A`, `B`, or `C`):
 
-		let rec u g x = (let f = u g in A)
+		let rec  u g x = (let f = u g in A)
 		in let rec g y = (let f = u g in B)
-		in let f = u g in C
+		in let                f = u g in
+		C
 
 	or, expanded into the form we've been working with:
 
 		let u = Y (\u g x. (\f. A) (u g)) in
-		let g = Y (\g y. (\f. B) (u g)) in
-		let f = u g
+		let g = Y (  \g y. (\f. B) (u g)) in
+		let f =                     u g in
+		C
 
+*	Here's the same strategy extended to three mutually-recursive functions. `f`, `g` and `h`:
+
+		let u = Y (\u g h x.      (\f. A) (u g h)) in
+		let w = Y (  \w h x. (\g. (\f. B) (u g h)) (w h)) in
+		let h = Y (    \h x. (\g. (\f. C) (u g h)) (w h)) in
+		let g =                                     w h in
+		let f =                            u g h in
+		D