Set-Sharing Is Not Always Redundant for Pair-Sharing

Abstract

Sharing among program variables is vital information when analyzing logic programs. This information is often expressed either as sets or as pairs of program variables that (may) share. That is, either as set-sharing or as pair-sharing. It has been recently argued that (a) set-sharing is interesting not as an observable property in itself, but as an encoding for accurate pair-sharing, and that (b) such an encoding is in fact redundant and can be significantly simplified without loss of pairsharing accuracy. We show that this is not the case when set-sharing is combined with other kinds of information, such as the popular freeness. © Springer-Verlag 2004.