Polynominal Learnability and Locality of Formal Grammars

We apply a complexity theoretic notion of feasible learnability called "polynomial learnability" to the evaluation of grammatical formalisms for linguistic description. We show that a novel, nontrivial constraint on the degree of "locality" of grammars allows not only context free languages but also a rich class of mildly context sensitive languages to be polynomially learnable. We discuss possible implications of this result to the theory of natural language acquisition. Comments University of Pennsylvania Department of Computer and Information Science Technical Report No. MSCIS-88-51. This technical report is available at ScholarlyCommons: http://repository.upenn.edu/cis_reports/591 POLYNOMIAL LEARNABILITY AND LOCALITY OF FORMAL GRAMMARS Naoki Abe MS-CIS-88-51 LlNC LAB 121 Department of Computer and Information Science School of Engineering and Applied Science University of Pennsylvania Philadelphia, PA 19104 July 1988 Acknowledgements: This research was supported in part by an IBM graduate fellowship, DARPA grant NO001 4-85-K-0018, NSF grants MCS-8219196-CER, IR184-10413-A02 and U.S. Army grants DAA29-84-K-0061, DAA29-84-9-0027. Polynomial Learnability and Locality of Formal Grammars Naolii Abe* Department of Computer and Information Science, University of Pennsylvania, Philadelphia, PA19104.