Explores inter-record linkage relationships of a bibliographic hypertext system through the use of descriptor term co-occurrences. Using term distribution and term exhaustivity data for an existing system, three models of term co-occurrence are developed and tested against the observed data. (Author/LRW)

Proposes split model for index term distribution in document set that uses rank function for high frequency terms and size function for low frequency terms; the point of transition is determined either empirically or by rule. Distributions to describe index term exhaustivity and term co-occurrence are considered briefly. (36 references) (EJS)

Reports algorithm for calculation of term discrimination values that is sufficiently fast in operation to permit use of exact values. Evidence is presented to show that relationship between term discrimination and term frequency is crucially dependent upon type of inter-document similarity measure used for calculation of discrimination values. (13…