Minimize linear mutual recursion by rule unfolding

We minimize the number of recursive predicates in a linear mutual recursion by the rule unfolding technique. The minimization is based on a newly proposed syntactic equivalence called the unfolding-equivalence. Algorithms for testing unfolding-equivalence and constructing an unfolding-equivalent recursion with the fewest possible number of recursive predicates are presented. We study the role of the unfolding technique in optimizing deductive databases through reducing these numbers