On the State Complexity of the Shuffle of Regular Languages
On the State Complexity of the Shuffle of Regular Languages
复制标题
论正则语言洗牌的状态复杂性
DOI:
10.1007/978-3-319-41114-9_6
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发表时间:
2015
期刊:
影响因子:
--
通讯作者:
Marek Szykuła
中科院分区:
文献类型:
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作者:
J. Brzozowski;Galina Jirásková;B. Liu;A. Rajasekaran;Marek Szykuła
We investigate the shuffle operation on regular languages represented by complete deterministic finite automata. We prove that $$f(m,n)=2^{mn-1} + 2^{(m-1)(n-1)}(2^{m-1}-1)(2^{n-1}-1)$$ is an upper bound on the state complexity of the shuffle of two regular languages having state complexitiesmandn, respectively. We also state partial results about the tightness of this bound. We show that there exist witness languages meeting the bound ifand, and also if. Moreover, we prove that in the subset automaton of the NFA accepting the shuffle, allstates can be distinguishable, and an alphabet of size three suffices for that. It follows that the bound can be met if allf(m,n) states are reachable. We know that an alphabet of size at leastmnis required provided that. The question of reachability, and hence also of the tightness of the boundf(m,n) in general, remains open.