Regular and Context-Free Pattern Languages over Small Alphabets
نویسندگان
چکیده
Pattern languages are generalisations of the copy language, which is a standard textbook example of a context-sensitive and noncontext-free language. In this work, we investigate a counter-intuitive phenomenon: with respect to alphabets of size 2 and 3, pattern languages can be regular or context-free in an unexpected way. For this regularity and context-freeness of pattern languages, we give several sufficient and necessary conditions and improve known results.
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ورودعنوان ژورنال:
- Theor. Comput. Sci.
دوره 518 شماره
صفحات -
تاریخ انتشار 2012