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Logic for Unambiguous Context-Free Languages (1604.04139v1)
Published 13 Apr 2016 in cs.FL, cs.CC, cs.DM, and cs.LO
Abstract: We give in this paper a logical characterization for unambiguous Context Free Languages, in the vein of descriptive complexity. A fragment of the logic characterizing context free languages given by Lautemann, Schwentick and Th\'erien [18] based on implicit definability is used for this aim. We obtain a new connection between two undecidable problems, a logical one and a language theoretical one.