@Article{ kl12ijfcs, author = "Kufleitner, Manfred and Lauser, Alexander", title = "Around Dot-Depth One", journal = "International Journal of Foundations of Computer Science", year = "2012", publisher = "World Scientific", pages = "1323--1339", volume = "23", number = "6", doi = "10.1142/S0129054112400552", url = "http://dx.doi.org/10.1142/S0129054112400552", abstract = "The dot-depth hierarchy is a classification of star-free languages. It is related to the quantifier alternation hierarchy of first-order logic over finite words. We consider subclasses of languages with dot-depth 1/2 and dot-depth 1 obtained by prohibiting the specification of prefixes or suffixes. As it turns out, these language classes are in one-to-one arXiv eprintsespondence with fragments of alternation-free first-order logic without min- or max-predicate, respectively. For all fragments, we obtain effective algebraic characterizations. Moreover, we give new proofs for the decidability of the membership problem for dot-depth 1/2 and dot-depth 1." }