@InProceedings{Areces1998a,
  author =       "C. Areces and V. Becher and S. Ferro",
  booktitle =    "Proceedings of ITALLC'98. Information Theoretic
                 Approaches to Logic, Language and Computation",
  title =        "Characterization Results for d-{H}orn Formulas",
  year =         "1998",
  abstract =     "We provide two di erent model theoretic
                 characterizations of a new fragment of first-order
                 logic which we call d-Horn formulas. This fragment is
                 dual to the well know Horn fragment and have the same
                 complexity for provability. The method used in the
                 characterization (syntactic translation functions
                 between formulas which are mimicked by translation
                 functions between models) might be applied to
                 characterize other first-order restrictions.",
  address =      "Hsi-Tow, Taiwan",
}