@InProceedings{Torre98ProhaireticDeontic,
  Title                    = {Prohairetic Deontic Logic (PDL)},
  Author                   = {van der Torre, L. and Tan, Y.},
  Booktitle                = {Logics in Artificial Intelligence. Proceedings of the 6th European Workshop on Logics in AI (JELIA'98)},
  Year                     = {1998},
  Pages                    = {77-91},
  Publisher                = {Springer},
  Series                   = {LNAI},
  Volume                   = {1489},

  Abstract                 = {In this paper we introduce Prohairetic Deontic Logic (PDL), a preference-based dyadic deontic logic. An obligation ‘α should be (done) if β is (done)’ is true if (1) no ¬α∧β state is as preferable as an α∧β state and (2) the preferred β states are α states. We show that the different elements of this mixed representation solve different problems of deontic logic. The first part of the definition is used to formalize contrary-to-duty reasoning, that for example occurs in Chisholm’s and Forrester’s notorious deontic paradoxes. The second part is used to make dilemmas inconsistent. PDL shares the intuitive semantics of preference-based deontic logics without introducing additional semantic machinery such as bi-ordering semantics or ceteris paribus preferences. },
  Url                      = {http://www.springerlink.com/content/gwactbelcpx3y2rc}
}