Theory contraction through base contraction (Q757344)

The author begins a study of the operations of contraction and revision as applied to bases of a theory, rather than to the theory (closed under logical consequence) itself. He focusses his discussion on the operations of ``safe'' contraction and revision as introduced by \textit{C. E. Alchourrón} and the reviewer [Stud. Logica 44, 405-422 (1985; Zbl 0605.03002)]. He also discusses the situations arising when the background consequence operation is taken as less than classical.