--- a/Implab/Automaton/IndexedAlphabetBase.cs	Mon Feb 29 18:41:01 2016 +0300
+++ b/Implab/Automaton/IndexedAlphabetBase.cs	Wed Mar 02 00:20:48 2016 +0300
@@ -8,6 +8,11 @@
     /// <summary>
     /// Indexed alphabet is the finite set of symbols where each symbol has a zero-based unique index.
     /// </summary>
+    /// <remarks>
+    /// Indexed alphabets are usefull in bulting efficient translations from source alphabet
+    /// to the input alphabet of the automaton. It's assumed that the index to the symbol match
+    /// is well known and documented.
+    /// </remarks>
     public abstract class IndexedAlphabetBase<T> : IAlphabetBuilder<T> {
         int m_nextId = 1;
         readonly int[] m_map;