DIRECT AUTOMATED INVERSION OF LOGIC GRAMMARS

Reversibility of logic grammars in natural language processing is desi rable for both theoretical and practical reasons. This paper addresses this topic in describing a new approach to automated inversion of log ic grammars: the Direct Inversion Approach (DIA). A logic grammar is i nverted by automatically altering the order of literals in the grammar and reformulating certain recursive procedures at compile time. The i nversion process results in a new executable grammar, which is evaluat ed top-down and left-to-right (using a standard Prolog interpreter), b ut not left-to-right with respect to the original grammar. The DIA imp roves upon related approaches not only in being fully automated and co mputationally tractable, but also with respect to the class of grammar s it is able to invert and the performance of the new executable gramm ar produced.