Avoiding Pitfalls When Learning Recursive Theories
Learning systems that express theories in rst-order logic must ensure that the theories are executable and, in particular, that they do not lead to innnite recursion. This paper presents a heuristic method for preventing innnite re-cursion in the (multi-clause) deenition of a recursive relation. The method has been implemented in the latest version of foil, but could also be used with any learning method that grows clauses from ground facts by repeated specialization. Results on several examples, including Ackermann's function, are presented.