Least fixed points in the Gödel-Löb logic
We prove a fixed-point theorem for positive schemes in the Gödel-Löb modal propositional logic GL which is similar to those proved in the author's paper reviewed above for intuitionistic and Grzegorczyk's logics. It is known that a theorem on the existence and uniqueness of a fixed point is valid in the logic GL for formulas in which all occurrences of the distinguished variable are within the scope of modalities. Here we consider a somewhat different family of formulas.
scientific article; zbMATH DE number 738970