Reasoning under inconsistency: A forgetting-based approach

In this paper, a fairly general framework for reasoning from inconsistent propositional basesis defined. Variable forgetting is used as a basic operation for weakening pieces of infor-mation so as to restore consistency. The key notion is that of recoveries, which are sets ofvariables whose forgetting enables restoring consistency. Several criteria for defining pre-ferred recoveries are proposed, depending on whether the focus is laid on the relative rele-vance of the atoms or the relative entrenchment of the pieces of information (or both). Ourframework encompasses several previous approaches as specific cases, including reasoningfrom preferred consistent subsets, and some forms of information merging. Interestingly,the gain in flexibility and generality offered by our framework does not imply a complexityshift compared to these specific cases.