Representation of sets on mass storage devices for information retrieval systems
Stuart T. Byrom, W. T. Hardgrave · 1973
Information retrieval systems utilizing Boolean operators to manipulate subsets of the data base require an efficient method of set representation. Commands in the user language permit the selection of subsets by retrieving occurrences in the data base that obey user specified conditions. Compound conditions may then be obtained by performing the traditional Boolean operators AND, OR, and NOT to selected subsets. Entries in the data base may be assigned identification numbers in order that the representations of subsets may be in the form of a set of positive identification numbers. Thus, the problem of manipulating large sets of occurrences reduces to one of efficiently representing subsets of positive integers.