Automata with two-sided pushdowns defined over free groups generated by reduced alphabets
نویسندگان
چکیده
This paper introduces and discusses a modification of pushdown automata. This modification is based on two-sided pushdowns into which symbols are pushed from both ends. These pushdowns are defined over free groups, not free monoids, and they can be shortened only by the standard group reduction. We demonstrate that these automata characterize the family of recursively enumerable languages even if the free groups are generated by no more than four symbols.
منابع مشابه
Two-sided Pushdown Automata over Free Groups
In the two-sided pushdown automata discussed in this paper, their two-sided pushdowns are introduced over free groups rather than free monoids. It is demonstrated that these automata with pushdowns introduced in this way characterize the family of recursively enumerable languages.
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ورودعنوان ژورنال:
- Kybernetika
دوره 43 شماره
صفحات -
تاریخ انتشار 2007