ylfink@water.UUCP (ylfink) (02/25/86)
DEPARTMENT OF COMPUTER SCIENCE UNIVERSITY OF WATERLOO SEMINAR ACTIVITIES COMPUTER SCIENCE COLLOQUIUM - Tuesday, March 4, 1986. Mr. Yannis Ioannidis of the University of California, Berkeley will speak on ``Processing Recursion in Deduc- tive Databases''. TIME: 3:30 PM ROOM: MC 1052 ABSTRACT Recursion appears to be one of the most important features of a database system enhanced with deductive power. In such an environment, it has traditionally been studied under the formalism of 1-st order logic, focusing on recursive Horn clauses. We reformulate the recursion problem in operator form, embedding it in a particular algebraic structure. This enables us to get more information about the mechanics of recursion. In particular, alternative processing techniques are revealed, which, depending on the database state, have the potential of being more efficient than the tradi- tional ones. The importance of including these alter- native algorithms in the strategy space of a recursion optimizer is illustrated by some examples.