• SearchLevel class fully describes the operations to be carried out on each level of the search
  
  
• At each level one can:
  
  
  • prune search paths - beam pruning and instance pruning
    
    
  • generate context-dependent symbols on the fly (unlimited left and right contexts)
    
    
  • generate N-symbol (N-gram for words) probabilities on the fly
    
    
  • compose levels into a lexical tree
    
    
  • maintain search statistics and paths
    
    
  • allow N-symbol decoding