English

A Note on Iterated Consistency and Infinite Proofs

Logic 2018-07-17 v2

Abstract

Schmerl and Beklemishev's work on iterated reflection achieves two aims: It introduces the important notion of Π10\Pi^0_1-ordinal, characterizing the Π10\Pi^0_1-theorems of a theory in terms of transfinite iterations of consistency; and it provides an innovative calculus to compute the Π10\Pi^0_1-ordinals for a range of theories. The present note demonstrates that these achievements are independent: We read off Π10\Pi^0_1-ordinals from a Sch\"utte-style ordinal analysis via infinite proofs, in a direct and transparent way.

Cite

@article{arxiv.1709.01540,
  title  = {A Note on Iterated Consistency and Infinite Proofs},
  author = {Anton Freund},
  journal= {arXiv preprint arXiv:1709.01540},
  year   = {2018}
}

Comments

This is a pre-print (before peer-review) of an article published in the Archive for Mathematical Logic. The final authenticated version is available online at https://doi.org/10.1007/s00153-018-0639-y. It can also be accessed via https://rdcu.be/2YJI (view only). Note that the journal version contains some improvements over the present pre-print

R2 v1 2026-06-22T21:33:59.508Z