Abstract.
In this paper we introduce context-free grammars and pushdown automata over infinite alphabets. It is shown that a language is generated by a context-free grammar over an infinite alphabet if and only if it is accepted by a pushdown automaton over an infinite alphabet. Also the generated (accepted) languages possess many of the properties of the ordinary context-free languages: decidability, closure properties, etc.. This provides a substantial evidence for considering context-free grammars and pushdown automata over infinite alphabets as a natural extension of the classical ones.
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Received November 27, 1995 / March 4, 1997
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Cheng, E., Kaminski, M. Context-free languages over infinite alphabets. Acta Informatica 35, 245–267 (1998). https://doi.org/10.1007/s002360050120
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DOI: https://doi.org/10.1007/s002360050120