Copyright © 2008 The Institute of Electronics, Information and Communication Engineers
Special Section on Foundations of Computer Science -- Papers -- Formal Language Theory |
On the Generative Power of Multiple Context-Free Grammars and Macro Grammars
1 The author is with the Graduate School of Information Science, Nara Institute of Science and Technology, Ikoma-shi, 630–0192 Japan. E-mail: seki{at}is.naist.jp, 2 The author is with Bioinformatics Center, Institute for Chemical Research, Kyoto University, Uji-shi, 611–0011 Japan.
| Abstract |
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Several grammars of which generative power is between context-free grammar and context-sensitive grammar were proposed. Among them are macro grammar and tree adjoining grammar. Multiple context-free grammar is also a natural extension of context-free grammars, and is known to be stronger in its generative power than tree adjoining grammar and yet to be recognizable in polynomial time. In this paper, the generative power of several subclasses of variable-linear macro grammars and that of multiple context-free grammars are compared in details.
Key Words: multiple context-free grammar, macro grammar, context-free tree grammar, generative power, linearity
Manuscript received April 2, 2007. Manuscript revised June 28, 2007.