9. A method as claimed in claim 8 , wherein said merging step includes identifying interchangeable symbols on the basis of predetermined merging evidence patterns.
9. A method as claimed in claim 8 , wherein said merging step includes identifying interchangeable symbols on the basis of predetermined merging evidence patterns. 10. A method as claimed in claim 9 , wherein said merging step includes determining whether symbols to be merged have compatible slot specification rules and return corresponding slots.