Proof theory for theories of ordinals. II: \(\Pi_{3}\)-reflection
The author extends his work in Part I [Ann. Pure Appl. Logic 122, 1--85 (2003; Zbl 1032.03049)] from the Mahlo case to \(\Pi_3\)-reflection. The analysis is given by use of ordinal diagrams defined by the author in J. Symb. Log. 65, 1375--1394 (2000; Zbl 0979.03043)].
scientific article; zbMATH DE number 2117325