Formal description of the inference engine in prolog

The purpose of the paper is to demonstrate the appropriateness and to present a formal description of the inference engine in Prolog. A non-formal description of the situation, when Prolog-system answers the questions, allows one to identify the key notions of the inference engine, although this description gives clear explanation for finding the solutions of simple problems only. The formal description of inference engine, on the other hand, helps to understand all the peculiarities of organization and managing the finding solutions for problems of different complexity. Since the Prolog programming presupposes deep understanding of the target validation process, the formal description of inference engine is quite important.