15. The computer-readable storage medium of claim 9 wherein the automaton comprises a tree having a sub tree corresponding to a predicate within one of the structured path expressions, wherein the sub tree is rooted at a node with the predicate.
15. The computer-readable storage medium of claim 9 wherein the automaton comprises a tree having a sub tree corresponding to a predicate within one of the structured path expressions, wherein the sub tree is rooted at a node with the predicate. 16. The computer-readable storage medium of claim 15 wherein the sub tree comprises a plurality of branches corresponding to conditions of the predicate, wherein the branches are associated with an aggregation operator representing how to combine the conditions of the predicate.