Booth, RMeyer, TVarzinczak, IWassermann, R2012-01-052012-01-052011-09Booth, R, Meyer, T, Varzinczak, I and Wassermann, R. 2011. On the link between partial meet, kernel, and infra contraction and its application to horn logic. Journal of Artificial Intelligence Research, Vol 42(2011), pp 31-531076-9757http://www.jair.org/media/3364/live-3364-5846-jair.pdfhttp://hdl.handle.net/10204/5434Copyright: 2011 Association for the Advancement of Artificial IntelligenceStandard belief change assumes an underlying logic containing full classical propositional logic. However, there are good reasons for considering belief change in less expressive logics as well. In this paper the authors build on recent investigations by Delgrande on contraction for Horn logic. They show that the standard basic form of contraction, partial meet, is too strong in the Horn case. This result stands in contrast to Delgrande's conjecture that orderly maxichoice is the appropriate form of contraction for Horn logic. They then define a more appropriate notion of basic contraction for the Horn case, influenced by the convexity property holding for full propositional logic and which they refer to as infra contraction. The main contribution of this work is a result which shows that the construction method for Horn contraction for belief sets based on our infra remainder sets corresponds exactly to Hansson's classical kernel contraction for belief sets, when restricted to Horn logic. This result is obtained via a detour through contraction for belief bases. They prove that kernel contraction for belief bases produces precisely the same results as the belief base version of infra contraction. The use of belief bases to obtain this result provides evidence for the conjecture that Horn belief change is best viewed as a `hybrid' version of belief set change and belief base change. One of the consequences of the link with base contraction is the provision of a representation result for Horn contraction for belief sets in which a version of the Core-retainment postulate features.enHorn logicPropositional logicArtificial intelligence researchStandard belief changeArtificial intelligencePartial meetKernelInfra contractionArticleBooth, R., Meyer, T., Varzinczak, I., & Wassermann, R. (2011). On the link between partial meet, kernel, and infra contraction and its application to horn logic. http://hdl.handle.net/10204/5434Booth, R, T Meyer, I Varzinczak, and R Wassermann "On the link between partial meet, kernel, and infra contraction and its application to horn logic." (2011) http://hdl.handle.net/10204/5434Booth R, Meyer T, Varzinczak I, Wassermann R. On the link between partial meet, kernel, and infra contraction and its application to horn logic. 2011; http://hdl.handle.net/10204/5434.TY - Article AU - Booth, R AU - Meyer, T AU - Varzinczak, I AU - Wassermann, R AB - Standard belief change assumes an underlying logic containing full classical propositional logic. However, there are good reasons for considering belief change in less expressive logics as well. In this paper the authors build on recent investigations by Delgrande on contraction for Horn logic. They show that the standard basic form of contraction, partial meet, is too strong in the Horn case. This result stands in contrast to Delgrande's conjecture that orderly maxichoice is the appropriate form of contraction for Horn logic. They then define a more appropriate notion of basic contraction for the Horn case, influenced by the convexity property holding for full propositional logic and which they refer to as infra contraction. The main contribution of this work is a result which shows that the construction method for Horn contraction for belief sets based on our infra remainder sets corresponds exactly to Hansson's classical kernel contraction for belief sets, when restricted to Horn logic. This result is obtained via a detour through contraction for belief bases. They prove that kernel contraction for belief bases produces precisely the same results as the belief base version of infra contraction. The use of belief bases to obtain this result provides evidence for the conjecture that Horn belief change is best viewed as a `hybrid' version of belief set change and belief base change. One of the consequences of the link with base contraction is the provision of a representation result for Horn contraction for belief sets in which a version of the Core-retainment postulate features. DA - 2011-09 DB - ResearchSpace DP - CSIR KW - Horn logic KW - Propositional logic KW - Artificial intelligence research KW - Standard belief change KW - Artificial intelligence KW - Partial meet KW - Kernel KW - Infra contraction LK - https://researchspace.csir.co.za PY - 2011 SM - 1076-9757 T1 - On the link between partial meet, kernel, and infra contraction and its application to horn logic TI - On the link between partial meet, kernel, and infra contraction and its application to horn logic UR - http://hdl.handle.net/10204/5434 ER -