Lower space bounds for accepting shuffle languages
Closure properties of hyper-minimized automata
Two deterministic finite automata are almost equivalent if they disagree in acceptance only for finitely many inputs. An automaton is hyper-minimized if no automaton with fewer states is almost equivalent to . A regular language is canonical if the minimal automaton accepting is hyper-minimized. The asymptotic state complexity () of a regular language is the number of states of a hyper-minimized automaton for a language finitely different from . In this paper we show that: (1)...
Lower Space Bounds for Accepting Shuffle Languages
In [6] it was shown that shuffle languages are contained in (log ) and in . In this paper we show that nondeterministic one-way logarithmic space is in some sense the lower bound for accepting shuffle languages. Namely, we show that there exists a shuffle language which is not accepted by any deterministic one-way Turing machine with space bounded by a sublinear function, and that there exists a shuffle language which is not accepted with less than logarithmic space even if we allow two-way nondeterministic...
Closure properties of hyper-minimized automata
Two deterministic finite automata are almost equivalent if they disagree in acceptance only for finitely many inputs. An automaton is hyper-minimized if no automaton with fewer states is almost equivalent to . A regular language is canonical if the minimal automaton accepting is hyper-minimized. The asymptotic state complexity () of a regular language is the number of states of a hyper-minimized automaton for a...
On the expressive power of the shuffle operator matched with intersection by regular sets
We investigate the complexity of languages described by some expressions containing shuffle operator and intersection. We show that deciding whether the shuffle of two words has a nonempty intersection with a regular set (or fulfills some regular pattern) is NL-complete. Furthermore we show that the class of languages of the form , with a shuffle language and a regular language , contains non-semilinear languages and does not form a family of mildly context- sensitive languages.
On the expressive power of the shuffle operator matched with intersection by regular sets
We investigate the complexity of languages described by some expressions containing shuffle operator and intersection. We show that deciding whether the shuffle of two words has a nonempty intersection with a regular set (or fulfills some regular pattern) is NL-complete. Furthermore we show that the class of languages of the form , with a shuffle language and a regular language , contains non-semilinear languages and does not form a family of mildly context- sensitive languages.
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