Readme updated

1 files changed, 6 insertions, 2 deletions

diff --git a/readme.md b/readme.md
index b153227..039dc24 100644
--- a/readme.md
+++ b/readme.md
@@ -20,8 +20,8 @@ the basic reification.
 
 Note that efficient culling of intermediate results is an ongoing concern, and
 it is recommended to minimise branching when making use of the Math functions.
-Do not attempt to run the `houses.adb` example program unless you have a very
-large amount of free memory.
+Do not attempt to run the `houses.adb` example program unless you have a large
+amount of free memory, around two gigabytes.
 
 
 
@@ -95,6 +95,10 @@ instead.
 All the Goal operations beyond the microKanren four take an array of Terms as
 input in order to allow for Conjunct to be reasonably implemented.
 
+The State datatype and the cache in the Collector package both make use of
+Vectors instead of Maps. This is done to reduce memory requirements, and the
+difference is considerable.
+
 
 
 #### Credits and Licensing