fix multiplication

[lambda.git] / lists_and_numbers.mdwn

diff --git a/lists_and_numbers.mdwn b/lists_and_numbers.mdwn
index 2f59e26..17b6dfd 100644 (file)
--- a/lists_and_numbers.mdwn
+++ b/lists_and_numbers.mdwn
@@ -295,12 +295,16 @@ Perhaps not as elegant as addition, but still decently principled.
 
 Multiplication is even more elegant. Consider that applying an arbitrary function s to a base value z *m × n* times is a matter of applying s to z *n* times, and then doing that again, and again, and so on...for *m* repetitions. In other words, it's a matter of applying the function (\z. n s z) to z *m* times. In other words, *m × n* can be represented as:
 
-<pre><code>    \s z. m (\z. n s z) z
-~~> \s z. m n s z</code></pre>
+       \s z. m (\z. n s z) z
 
-which eta-reduces to:
+which, doing an eta-reduction and permitting ourselves the `&#8728;` notation, is:
+
+<pre><code>\s z. (m &#8728; n) s z</code></pre>
+
+and some more eta-reduction gives us:
+
+<pre><code>m &#8728; n</code></pre>
 
-       m n
 
 Isn't that nice?