From: Chris <chris.barker@nyu.edu>
Date: Mon, 16 Mar 2015 16:08:26 +0000 (-0400)
Subject: edits
X-Git-Url: http://lambda.jimpryor.net/git/gitweb.cgi?p=lambda.git;a=commitdiff_plain;h=cb9c6590ec969e34555d9c9f56758c3e6c252ce5

edits
---

diff --git a/topics/_week7_monads.mdwn b/topics/_week7_monads.mdwn
index 75bc2051..3f2955e9 100644
--- a/topics/_week7_monads.mdwn
+++ b/topics/_week7_monads.mdwn
@@ -50,3 +50,25 @@ would write
 
 <table border=2px><td>Int</td></table>
 
+for the type of a boxed Int.
+
+At the most general level, we'll talk about *Kleisli arrows*:
+
+P -> <table border=2px><td>Q</td></table>
+
+A Kleisli arrow is the type of a function from objects of type P to
+objects of type box Q, for some choice of type expressions P and Q.
+For instance, the following are arrows:
+
+Int -> <table border=2px><td>Bool</td></table>
+
+Int List -> <table border=2px><td>Int List</td></table>
+
+Note that the left-hand schema can itself be a boxed type.  That is,
+if `α List` is our box type, we can write the second arrow as
+
+<table border=2px><td>Int</td></table>
+->
+<table border=2px><td><table
+border=2px><td>Int</td></table></td></table>
+