The difference ´Ò Ò ½µ between Ò-grams and´Ò ½µ-grams is, once again, measured by Kullback-Leibler divergence.
´Ò Ò ½µ Ã ÄÈ´Ý Ü Ò µ È´Ý Ü´Ò ½µ µ If ´Ò Ò ½µ is smaller than another predefined threshold SHR , then´Ò ½µ-grams are used instead of Ò-grams.