tweak inf arithmetic comment

diff --git a/exercises/_assignment4.mdwn b/exercises/_assignment4.mdwn
index 226741e..38e3180 100644 (file)
--- a/exercises/_assignment4.mdwn
+++ b/exercises/_assignment4.mdwn
@@ -117,8 +117,8 @@ is unchanged after adding 1 to it.  It makes a certain amount of sense
 to use this object to model arithmetic infinity.  For instance,
 depending on implementation details, it might happen that `leq n ξ` is
 true for all (finite) natural numbers `n`.  However, the fixed point
-you found for `succ` may not be a fixed point for `mult n` or for
-`exp n`.
+you found for `succ` and `(+n)` may not be a fixed point for `(*n)` or for
+`(^n)`.
 
 
 ## Mutually-recursive functions ##