Work on declarative debugging [47] showed great promise, but the non-declarative features of Prolog do not make the use of the technique straightforward. The development of the Gödel language [44], largely through the ESPRIT BRA 3012, COMPULOG, means that there is now an opportunity to advance this work.
In the area of parallel program behavior and analysis great potential is expected from tools which are based on visualization techniques [62, 71, 28, 7, 29, 1, 36, 38, 72].
A new semantics for logic programs with negation ([25], [26], [27]), well adapted to the verification of declarative properties of logic programs, and a new proof method (called the annotation method) have been designed. It has been shown that this method can be applied to proving run-time properties as well [23]. Validation tools for debugging and proving properties ([24], [6]) have been defined. Experimental tools have been built and used in real software projects [64, 68].