A NOTE ON PREDICATIVE ORDINAL ANALYSIS I: ITERATED COMPREHENSION AND TRANSFINITE INDUCTION

Autor: Sato Kentaro
Rok vydání: 2019
Předmět:
Zdroj: The Journal of Symbolic Logic. 84:226-265
ISSN: 1943-5886
0022-4812
DOI: 10.1017/jsl.2017.71
Popis: We determine the proof-theoretic ordinals (i) of ${\cal C} - {\bf{TI}}[\alpha ]$, the transfinite induction along α, for any hyperarithmetical level ${\cal C}$, in the first order setting and (ii) of any combination of iterated arithmetical comprehension and ${\cal C} - {\bf{TI}}[\alpha ]$ for ${\cal C}\, \equiv \,{\rm{\Pi }}_k^i ,{\rm{\Sigma }}_k^i$ ($i\, = \,0,1$) in the second order setting.
Databáze: OpenAIRE