25. A method as claimed in claim 23 , wherein said merging step includes identifying interchangeable symbols on the basis of predetermined merging evidence patterns.
25. A method as claimed in claim 23 , wherein said merging step includes identifying interchangeable symbols on the basis of predetermined merging evidence patterns. 27. A method as claimed in claim 25 , wherein said evidence patterns represent relationships between rules indicating a merger and corresponding rule formats to be generated when one of said relationships exist between said rules.