A set of index keys is included in an index search system that are
associated with the scope of the search rather than the content of the
documents that are the target of the search. These scope related index
keys, or scope keys allows the scope of the search to be selected,
reducing the number of documents that a search is required to sift
through to obtain results. Furthermore, compound scopes are recognized
and stored such that an index of complex search scopes is provided to
eliminate rehashing of the searches based on these complex search scopes.