• In an N-symbol search, any symbol can follow any other symbol
  
  
• The histories are based on the N most recent symbols
  
  N-symbol history length = 4 TR0 = Trace(zero, nine, two, one, four, seven) TR0.History = (seven, four, one, two);
  
  
• Next symbols are generated on the fly rather than expanding the N-symbols into a graph