minor README fix

diff --git a/README b/README
index b4c986e..92accab 100644 (file)
--- a/README
+++ b/README
@@ -52,8 +52,8 @@ Description about that design is at the epointsystem.org website:
        https://www.epointsystem.org/trac/website
 
 
-Design
-------
+Overview
+--------
 
 An epoint server is a large billboard, where clients can publish
 draft documents (acknowledging debt, "i owe you")
@@ -76,16 +76,15 @@ The balance of a client with respect to an issuer is the
 agregate value of all the drafts that transfer debt of the given
 issuer to or from the given client.
 
-The main constraint is that a holder cannot transfer more debt
-than its balance. Such drafts are invalid and must be rejected.
-If the issuer is the drawer of a draft then there is no such
-constraint. The balance of the issuer is <=0 and the balance of
-a holder of the issuer's debt is >=0 at any given time. All the
-balances together give 0.
+An important constraint of the system is that a holder cannot
+transfer more debt than its balance. Such drafts are invalid and
+must be rejected. If the issuer is the drawer of a draft then
+there is no such constraint. The balance of the issuer is <=0
+and the balance of a holder of the issuer's debt is >=0 at any
+given time. All the balances together give 0.
 
 The main purpose of the server is to make it easy to check the
-current balance of a client with respect to an issuer at any
-given time.
+current balance of a client.
 
 To achieve this the server needs to store all the drafts and the
 public keys of the clients so the drafts are verifiable. The