Inductive inference from positive data is powerful
COLT '90 Proceedings of the third annual workshop on Computational learning theory
Learnable classes of categorial grammars
Learnable classes of categorial grammars
Handbook of Logic and Language
Handbook of Logic and Language
On Limit Points for Some Variants of Rigid Lambek Grammars
ICGI '02 Proceedings of the 6th International Colloquium on Grammatical Inference: Algorithms and Applications
Lambek Grammars Based on Pregroups
LACL '01 Proceedings of the 4th International Conference on Logical Aspects of Computational Linguistics
Categorial grammars determined from linguistic data by unification
Categorial grammars determined from linguistic data by unification
Rigid Lambek grammars are not learnable from strings
COLING '02 Proceedings of the 19th international conference on Computational linguistics - Volume 1
k-Valued non-associative Lambek grammars are learnable from generalized functor-argument structures
Theoretical Computer Science - Logic, language, information and computation
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This paper is concerned with learning categorial grammars in Gold's model. In contrast to k-valued classical categorial grammars, k-valued Lambek grammars are not learnable from strings. This result was shown for several variants but the question was left open for the weakest one, the non-associative variant NL.We show that the class of rigid and k-valued NL grammars is unlearnable from strings, for each k; this result is obtained by a specific construction of a limit point in the considered class, that does not use product operator.Another interest of our construction is that it provides limit points for the whole hierarchy of Lambek grammars, including the recent pregroup grammars.Such a result aims at clarifying the possible directions for future learning algorithms: it expresses the difficulty of learning categorial grammars from strings and the need for an adequate structure on examples.