Adding forward chaining and truth maintenance to Prolog

A description is given of P/sub fc/, a simple package which supplies a forward chaining facility in Prolog. P/sub fc/ is intended to be used in conjunction with ordinary Prolog programs, allowing the programmer to decide whether to encode a rule as a forward-chaining P/sub fc/ rule or a backward-chaining Prolog one. Like other programming languages, P/sub fc/ programs have a declarative interpretation as well as a clear and predictable procedural one. A truth maintenance system built into P/sub fc/ system maintains consistency and makes derivations available for applications. Finally, P/sub fc/ is designed to be relatively efficient and unobtrusive.<
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