In this method the value of an attribute is compressed into a binary word of width with a fixed number of bits set to . This number is called the weight. The problem is how to represent variables so that they can match with anything. In COLOMB three possibilities to do this are proposed.
The main advantage of this method is that one can currently construct hardware that handles up to clauses and more in the presented manner. Together with the linear searching hash-function one reaches a very high efficiency. Another key property is that m-in-n-coding results in highly compressed code, so that large clause code can be stored separately (externally) from the small index code and only single rules are loaded.