4. The system of claim 1 , wherein the candidate list generator module is further to apply at least one token generation rule to the validated token pairs to identify invalid token pairs.
4. The system of claim 1 , wherein the candidate list generator module is further to apply at least one token generation rule to the validated token pairs to identify invalid token pairs. 5. The system of claim 4 , wherein an invalid token pair is one resulting in a large number of data items in unrelated categories as a result from search.