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arXiv · 1301.2181

Equivalence of Deterministic One-Counter Automata is NL-complete

Stanislav Böhm·Stefan Göller·Petr Jančar
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Abstract

We prove that language equivalence of deterministic one-counter automata is NL-complete. This improves the superpolynomial time complexity upper bound shown by Valiant and Paterson in 1975. Our main contribution is to prove that two deterministic one-counter automata are inequivalent if and only if they can be distinguished by a word of length polynomial in the size of the two input automata.

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Stanislav Böhm, Stefan Göller, Petr Jančar. 2013-01-10. Equivalence of Deterministic One-Counter Automata is NL-complete. https://arxiv.org/abs/1301.2181

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