2631	 An Information-Theoretic Approach to Text Searching in Direct Access Systems	 Using direct access computer files of bibliographic information an attempt is made to overcome one of the problems often associated with information retrieval namely the maintenance and use of large dictionaries the greater part of which is used only infrequently. A novel method is presented which maps the hyperbolic frequency distribution. This is more suited to implementation on storage devices. This method treats text as a string of characters rather than words bounded by spaces and chooses subsets of strings such that their frequencies of occurrence are more even than those of word types. The members of this subset are then used as index keys for retrieval. The rectangular distribution of key frequencies results in a much simplified file organization and promises considerable cost advantages. text searching information theory file organization direct access information retrieval character string bit vector
