Abstract
This paper is a contribution to the problem of effectively determining the dot-depth of a star-free language, a problem in the theory of automata and formal languages with close connections to algebra and formal logic. We conjecture an effective criterion for determining whether a given language has dot-depth 2. The condition is shown to be necessary in general, and sufficient for languages over a two-letter alphabet. The condition involves a novel use of categories in the study of semigroup-theoretic problems.
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© 1986 Springer-Verlag Berlin Heidelberg
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Straubing, H. (1986). Semigroups and languages of dot-depth 2. In: Kott, L. (eds) Automata, Languages and Programming. ICALP 1986. Lecture Notes in Computer Science, vol 226. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-16761-7_91
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DOI: https://doi.org/10.1007/3-540-16761-7_91
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Online ISBN: 978-3-540-39859-2
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