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patternModerate

Relationship of algorithm complexity and automata class

Submitted by: @import:stackexchange-cs··
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automataalgorithmandclasscomplexityrelationship

Problem

I have been unable to find a graph depicting or text answering the following question: Is there a direct relationship between the complexity of an algorithm (such as best / worst case of quick sort), and class of automata that can implement the algorithm. For example is there a range of complexity push down automata can express? If the answer is yes to said question is there a resource depicting the relationship? Thanks!

Solution

Here are some known results:

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$\mathsf{REG} = \mathsf{DSPACE}(1) = \mathsf{NSPACE}(1) = \mathsf{DSPACE}(o(\log\log n)) = \mathsf{NSPACE}(o(\log\log n))$, where $\mathsf{REG}$ is the set of regular languages. For proofs, see the Wikipedia page on $\mathsf{DSPACE}$.

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$\mathsf{DCFL} \subseteq \mathsf{SC}$, where $\mathsf{DCFL}$ is the set of deterministic context-free languages, and $\mathsf{SC}$ is Steve's class. See the Wikipedia page on $\mathsf{DCFL}$.

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$\mathsf{NL} \subseteq \mathsf{LOGCFL} \subseteq \mathsf{AC^1}$, where $\mathsf{LOGCFL}$ is the set of languages logspace-reducible to a context-free language. See the Wikipedia page on $\mathsf{LOGCFL}$, which also gives some languages complete for $\mathsf{LOGCFL}$ under logspace reductions.

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$\mathsf{CSL} = \mathsf{NSPACE}(n)$, where $\mathsf{CSL}$ is the set of context-sensitive languages. See the Wikipedia page on $\mathsf{CSL}$.

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The class of languages accepted by deterministic nonerasing PDAs is $\mathsf{DSPACE(n\log n)}$, and the class of languages accepted by non-deterministic nonerasing PDAs is $\mathsf{NSPACE}(n^2)$. See the Wikipedia page on PDAs.

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Two-stack automata are equivalent in power to Turing machines, but restricting the automata results in weaker models. See a technical report of San Pietro.

Context

StackExchange Computer Science Q#52748, answer score: 11

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