Schema Evolution publication categorizer

In earlier work, Bancilhon and Spyratos introduced the concept of a complement to a
database schema, and showed how this notion could be used in theories of decomposition and
update semantics. However, they also showed that, except in trivial cases, even minimal complements
are never unique, so that many desirable results, such as canonical decompositions,
cannot be realized. Their work dealt with database schemata which are sets and database
mappings which are functions, without further structure. In this work, we show that by adding