6. The method of claim 5 , wherein the step of retrieving a corresponding fragment is selectively determined according to the relevance score of the associated subtree identifier, wherein a first subtree identifier with a higher relevance score is selected preferentially over an alternate subtree identifier with a lower relevance score.
5. The method of claim 1 , wherein each subtree identifier further comprises a relevance score, the relevance score indicating a likelihood of the subtree including a particular target query element, wherein the relevance score is normalized to the number of step queries contained in the associated subtree fragment.