Contraction in interrogative belief revision
\textit{E. J. Olsson} and \textit{D. Westlund} [``On the role of the research agenda in epistemic change'', Erkenntnis 65, No.~2, 165--183 (2006; Zbl 1202.03031)] proposed an account of belief change called ``interrogative belief revision''. On that account epistemic states, which in the AGM paradigm are closed sets of sentences, are complemented by research agendas. Olsson and Westlund provided a simple method of expanding such agendas; the purpose of the paper under review is to give an account of their contraction. The methods employed are semantic, using Grove's system of spheres, and the constructions are guided by an informal ``principle of continuity'' according to which long-term research interests remain intact throughout changes of belief.
scientific article; zbMATH DE number 5710630