A number of parallel logic programming systems, which have been shown to be capable of significant speedups over state of the art sequential Prolog systems, are already being used as platforms by the project partners. These include &-Prolog [39] (developed at Madrid), Muse [2, 3] (developed at SICS, and recently incorporated into the SICStus Prolog system), and ElipSys [5] (developed at ECRC). The ElipSys execution platform, a prototype of which was developed as part of ESPRIT Project 2025, EDS, supports OR-parallelism as well as a framework for implementing constraint solvers and a close coupling to databases. Muse is a well established execution platform that allows Prolog to be executed in parallel by exploiting OR-parallelism. The &-Prolog system is also a well established parallel Prolog system that exploits (independent) AND-parallelism.
A matter of great interest is the combination of the capabilities of these systems, as well as those of other languages, both from the point of view of concurrency and constraint support.
The Andorra Kernel Language (AKL) is a new concurrent logic language developed by SICS with a large potential for parallel execution. It provides the programming paradigms of search-oriented languages such as Prolog, process-oriented languages such as GHC, and the constraint logic programming languages in a unified framework.
A proposal for combining Muse and &-Prolog into one system to exploit their two sources of parallelism while maintaining the high efficiency of both systems is represented by the ACE model [35]. We refer to a further enhancement of this model which also supports constraint solving (and explicit concurrency) in the same framework as Ciao --(Concurrent,) Constraint, Independence-based And/Or parallel Prolog [42].