Abstract. Binary relational algebra provides semantic foundations for major areas of computing, such as database design, state-based specification, and functional programming. Remarkably, static checking support in these areas fails to exploit the full semantic content of relations. In particular, properties such as the simplicity or injectivity of relations are not statically enforced in operations that manipulate relations, such as database queries, state transitions, or composition of functional components. We describe how a pointfree treatment of relations, their properties, their operators, and the laws that govern them can be captured in a type-directed strategic rewriting system for transformation of relational expressions. This rewriting tool can be used to simplify relational proof obligations and ultimately reduce them to tautologies. We demonstrate how such reductions provide extended static checking (ESC) for design contraints commonly found in software modeling and development.

This document outlines some of the present research interests of most members of the Department who are in a position to supervise the research of students entering during 1999/2000 academic year. The sections are simply arranged by alphabetical order of the potential supervisors' names. Where a supervisor is part of a research group this is indicated. In addition to describing some possible topics that a new research student could pursue, this document should enable identification of a supervisor whose research interests and expertise are likely to overlap with those of the applicant. Since many supervisors are willing to be involved in research that is related to the topics they list, informal correspondence with likely supervisors is encouraged, and has often proved a useful prelude to a formal application. Members of the Department can be contacted by sending electronic mail to firstname.lastname@cs.york.ac.uk. Readers without access to electronic mail facilities can contact members of the Department at: