We present a theory of qualitative rigid body mechanics and describe a program that uses this theory to compute qualitative dynamic simulations. The program works directly from a qualitative representation of geometry (qc-space). It employs a new qualitative representation for forces that reduces ambiguity in force sums and hence reduces branching.

In this paper we describe progress towards a theory of tran-formational program development. The transformation rules are based on a theory of contextual equivalence for functional languages with imperative features. Such notions of equivalence are fundamental for the process of program speciication, derivation, transformation, reenement and other forms of code generation and optimization. This...

Extended abduction introduced by Inoue and Sakama ( 1995 ) generalizes traditional abduction in the sense that it can compute negative explanations by removing hypotheses from a nonmonotonic background theory, rather than only adding them. Also, it has a mechanism of computing anti-explanations to unexplain negative observations. Such extended abduction not only enhances reasoning ability of tr...

A valid compiler optimisation transforms a block in a program without introducing new observable behaviours to the program as a whole. Deciding which optimisations are valid can be difficult, and depends closely on the semantic model of the programming language. Axiomatic relaxed models, such as C++11, present particular challenges for determining validity, because such models allow subtle effe...