4. The method of claim 2 wherein the sub-path definition comprises a modified path expression configured to match a plurality of path expressions corresponding to the plurality of covered descendant elements.
4. The method of claim 2 wherein the sub-path definition comprises a modified path expression configured to match a plurality of path expressions corresponding to the plurality of covered descendant elements. 5. The method of claim 4 wherein determining that the clause can be processed by the inverted multi-path index includes determining that the path expression in the clause matches the modified path expression of the sub-path definition and that the index property can produce an indexed value satisfying the clause.