From 3f744db8b949506facecace876c9273cf0e94535 Mon Sep 17 00:00:00 2001
From: wadler <wadler@inf.ed.ac.uk>
Date: Fri, 16 Feb 2018 17:27:02 -0200
Subject: [PATCH] updated index

---
 index.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/index.md b/index.md
index e9cdeec5..ad747345 100644
--- a/index.md
+++ b/index.md
@@ -28,6 +28,7 @@ http://homepages.inf.ed.ac.uk/wadler/
   - [Isomorphism: Isomorphism and embedding](Isomorphism)
   - [Logic: Logic](Logic)
   - [Lists: Lists and other data types](Lists)
+  - [Decidable: Booleans and decision procedures](Decidable)
 
   - [PropertiesAns: Solutions to exercises](PropertiesAns) 
   - [RelationsAns: Solutions to exercises](RelationsAns)