formal (theoretical) treatment of database indices

Almost everytime I see indices (indexes?) mentioned in text books or papers, it seems they are relagated to the query optimization section. Algebra/Calculus level primitives never take an index into account. I'm wondering if there has been any work done on making indices more important at a theoretical level. I'll appreciate any pointers. Thanks. Received on Wed Oct 05 2005 - 08:16:30 CDT