From: jim Date: Mon, 23 Feb 2015 19:17:05 +0000 (-0500) Subject: delete cruft X-Git-Url: http://lambda.jimpryor.net/git/gitweb.cgi?p=lambda.git;a=commitdiff_plain;h=8950982eae04ec4ca70862e23122256b526b591b delete cruft --- diff --git a/exercises/assignment3_answers.mdwn b/exercises/assignment3_answers.mdwn index 7530534f..6aa5d750 100644 --- a/exercises/assignment3_answers.mdwn +++ b/exercises/assignment3_answers.mdwn @@ -238,23 +238,6 @@ Reduce the following forms, if possible: Using the mapping specified in this week's notes, translate the following lambda terms into combinatory logic: - -Let's say that for any lambda term T, [T] is the equivalent Combinatory Logic term. Then we define the [.] mapping as follows. - - 1. [a] = a - 2. [(\aX)] = @a[X] - 3. [(XY)] = ([X][Y]) - -Wait, what is that @a ... business? Well, that's another operation on (a variable and) a CL expression, that we can define like this: - - 4. @aa = I - 5. @aX = KX if a is not in X - 6. @a(Xa) = X if a is not in X - 7. @a(XY) = S(@aX)(@aY) - - - -
1. `[\x x] = @x x = I`
2. `[\x y. x] = @x [\y. x] = @x. (@y x) = @x (Kx) = S (@x K) (@x x) = S (KK) I`; in general expressions of this form `S(KM)I` will behave just like `M` for any expression `M`