Undecidability of the Lambek Calculus with Subexponential and Bracket Modalities
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چکیده
Morrill and Valent́ın in the paper “Computational coverage of TLG: Nonlinearity” considered two extensions of the Lambek calculus with socalled “exponential” modalities. These calculi serve as a basis for describing fragments of natural language via categorial grammars. In this paper we show undecidability of derivability problems in these two calculi. On the other hand, restricted fragments of them are decidable and therefore can be used in practice.
منابع مشابه
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تاریخ انتشار 2017