• HDR Defended on :
  • Mar 3, 2010 • Salle des thèses, Faculté des Sciences, Lens.


This work is situated in the field of logics for artificial intelligence, and concerns more precisely the modeling and representation of knowledge and reasoning (KR).

We are interested in the problem of reasoning within the presence of incoherence. Depending on the additional information available, this leads to different frameworks, requiring specific reasoning methods:

  • Inconsistency: no additional information is available. It is therefore necessary to obtain coherent (reasonable) conclusions from an inconsistent set of information.

  • Revision: one of the formulas is more important than the others. This formula must be kept, while eliminating inconsistencies.

  • Merge: the formulas come from different sources. We must then define a coherent base from this information, taking into account the location of this information (with majority arguments for example).

  • Negotiation: the formulas come from different sources, as for the fusion, but the sources keep the control of the modifications of their formulas. We must therefore take into account possible interactions (coalitions, etc.).

Our approach is mainly axiomatic, i.e. we try to find logical characterizations for the different reasoning methods. We present our work concerning these four frameworks, in particular the characterizations obtained for inconsistency measures, iterated revision, and fusion; as well as the first results concerning negotiation.

Keywords: Artificial Intelligence, Reasoning, Inconsistency, Inference, Paraconsistent logics, Inconsistency measurement, Review, Fusion, Negotiation.



  • Gerhard Brewka (Professor at the University of Leipzig)
  • Marie-Christine Rousset (Professor at the University of Grenoble)
  • Torsten Schaub (Professor at the University of Potsdam)


  • Salem Benferhat (Professor at the University of Artois)
  • Andreas Herzig (Director of Research at CNRS - IRIT)
  • David Makinson (Professor at the London School of Economics)


  • Pierre Marquis (Professor at the University of Artois)