CKRew (CKR datalog rewriter) provides a datalog translation of OWL2-RL based CKR and supports reasoning with global defeasible axioms (or justifiable exceptions). CKRew is implemented as an extension of the DL to datalog rewriter DReW and provides a command line utility for the translation of CKRs represented as RDF/TRIG files.


  • CKR expressible in OWL2-RL
  • Option for defeasible KB in DL-Lite_R (OWL2 QL)
  • Input as N3 or TRIG files.
  • Datalog translation based on DReW rewriter.
  • Permits expression of defeasible global axioms (OWL axioms annotated with ckr:defeasible).
  • Available demo examples to show behaviour with non-monotonic axiom propagation.
  • Available testsets for scalability and defeasibility evaluation tests.


  • 2021-05-18: CKRew 1.6 package released
  • 2020-06-05: CKRew 1.5.1 package released
  • 2020-05-04: CKRew 1.5 package released
  • 2016-12-07: CKRew 1.4 package released
  • 2015-12-14: CKRew 1.3 package released
  • 2015-11-11: CKRew site launched

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Last Published: 2021/05/19.

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