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The class of languages recognizable by 1-way quantum finite automata is not closed under union

Maris Valdats
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Abstract

In this paper we develop little further the theory of quantum finite automata (QFA). There are already few properties of QFA known, that deterministic and probabilistic finite automata do not have e.g. they cannot recognize all regular languages. In this paper we show, that class of languages recognizable by QFA is not closed under union, even not under any Boolean operation, where both arguments are significant.

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Maris Valdats. 2000-01-04. The class of languages recognizable by 1-way quantum finite automata is not closed under union. https://arxiv.org/abs/quant-ph/0001005

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