### Technical Report No. 66, January 1995 - Abstract

**Stefan Schrödl:**

*An Extension of Explanation-Based Generalization to Negation as Failure*

Implementations of *Explanation-Based Generalization (EBG)* within
a logic-programming environment, as e.g.
the well-known PROLOG-EBG algorithm, are able to
generalize the proof of a goal
from a *definite* (i.e.Horn clause) domain theory. However, it is a
fact that practical applications frequently require the enhanced
expressiveness of *negations* in rule bodies. Specifically, this is the
case for the domain of game playing, where traditional EBG has
turned out to be inadequate. In this paper we present an
approach which extends EBG to this more general setting; it is
described in the form of a transformation system, and comprises Siqueira and
Puget's method of *Explanation-Based Generalization of Failures*
for definite programs.
For the case that both domain theory and training example are represented as
*allowed* normal programs, we prove that the derived clause
satisfies the standard requirements for EBG, namely
*operationality* , *sufficiency*, and
*correctness*. Furthermore, a meta-interpreter implementation of the
transformation system is provided.

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