کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
4950669 | 1364297 | 2017 | 16 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Complexity of universality and related problems for partially ordered NFAs
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی کامپیوتر
نظریه محاسباتی و ریاضیات
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Complexity of universality and related problems for partially ordered NFAs Complexity of universality and related problems for partially ordered NFAs](/preview/png/4950669.png)
چکیده انگلیسی
Partially ordered NFAs (poNFAs) are NFAs where cycles occur only in the form of self-loops. A poNFA is universal if it accepts all words over its alphabet. Deciding universality is PSpace -complete for poNFAs. We show that this remains true when restricting to fixed alphabets. This is nontrivial since standard encodings of symbols in, e.g., binary can turn self-loops into longer cycles. A lower coNP -complete complexity bound is obtained if all self-loops in the poNFA are deterministic. We find that such restricted poNFAs (rpoNFAs) characterize R-trivial languages, and establish the complexity of deciding if the language of an NFA is R-trivial. The limitation to fixed alphabets is essential even in the restricted case: deciding universality of rpoNFAs with unbounded alphabets is PSpace -complete. Consequently, we obtain the complexity results for inclusion and equivalence problems. Finally, we show that the languages of rpoNFAs are definable by deterministic (one-unambiguous) regular expressions.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Information and Computation - Volume 255, Part 1, August 2017, Pages 177-192
Journal: Information and Computation - Volume 255, Part 1, August 2017, Pages 177-192
نویسندگان
Markus Krötzsch, TomáÅ¡ Masopust, Michaël Thomazo,