From 03bae43bc16f1f8dc98cfe2dab15264bc129beb1 Mon Sep 17 00:00:00 2001
From: jim <jim@web>
Date: Thu, 19 Mar 2015 18:43:03 -0400
Subject: [PATCH] add mappable laws

---
 topics/week7_introducing_monads.mdwn | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/topics/week7_introducing_monads.mdwn b/topics/week7_introducing_monads.mdwn
index b3ab5aa9..adcf0cc2 100644
--- a/topics/week7_introducing_monads.mdwn
+++ b/topics/week7_introducing_monads.mdwn
@@ -127,7 +127,11 @@ certain useful guarantees.
 if there is a `map` function defined for that box type with the type given above. This
 has to obey the following Map Laws:
 
-    TODO LAWS
+    <code>map (id : α -> α) = (id : <u>α</u> -> <u>α</u>)</code>  
+    <code>map (g ○ f) = (map g) ○ (map f)</code>
+
+    Essentially these say that `map` is a homomorphism from `(α -> β, ○, id)` to <code>(<u>α</u> -> <u>β</u>, ○', id')</code>, where `○'` and `id'` are `○` and `id` restricted to arguments of type <code><u>_</u></code>.
+
 
 *   ***MapNable*** (in Haskelese, "Applicatives") A Mappable box type is *MapNable*
        if there are in addition `map2`, `mid`, and `mapply`.  (Given either
-- 
2.11.0