Abstract
We propose a new class of non-real-time deterministic pushdown automata (dpda's), named dpda's having the weak segmental property (WSP), and show that the equivalence problem is solvable for two dpda's, one of which is in this class. The equivalence checking algorithm to prove this problem is a further extended direct branching algorithm of Tomita; and with the new skipping step combined with the type B′ replacement of Oyamaguchi, Inagaki and Honda. The algorithm is still relatively simple. The class of dpda's given above is one of the widest known subclasses of proper dpda's (introduced by Ukkonen); with the decidable extended equivalence problem.
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This work was supported in part by Grants-in-Aid for Scientific Research Nos. 58550240 and 62550259 from the Ministry of Education, Science and Culture, Japan.
Presently with the Ome Works, Toshiba Corporation, Ome, Tokyo 198, Japan.
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Tomita, E., Seino, K. The extended equivalence problem for a class of non-real-time deterministic pushdown automata. Acta Informatica 32, 395–413 (1995). https://doi.org/10.1007/BF01178385
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DOI: https://doi.org/10.1007/BF01178385