OPTIMAL F-GRAPHS FOR BALANCED FAMILIES OF SETS.

This paper covers combinatorial problems related to certain generalizations of Ghosh's notion of consecutive retrieval file organization with redundancy. Identifying a query with the set of records relevant to it, the authors restrict their attention to those query and record sets where the corresponding family of sets of records is balanced, i. e. for any k, the cardinality of the intersection of any k sets in the family is dependent only on k. For such families of sets we consider organizations where any occurrence of a record has at most one intermediate successor. These include organizations of a linear, cyclic and directed tree structure.