English

There is no maximal decidable expansion of the $\langle \mathbb{N} ,\{ < \} \rangle$ structure

Logic 2022-11-30 v3

Abstract

We are going to prove that if the theory of a structure M=N,Σ\mathcal M=\langle \mathbb{N}, \Sigma \rangle is decidable and the standard order << on natural numbers N\mathbb{N} is definable in M\mathcal M, then there is a nontrivial decidable expansion of M\mathcal M

Cite

@article{arxiv.1911.09059,
  title  = {There is no maximal decidable expansion of the $\langle \mathbb{N} ,\{ < \} \rangle$ structure},
  author = {Sergei Soprunov},
  journal= {arXiv preprint arXiv:1911.09059},
  year   = {2022}
}

Comments

found an error in the proof of statement 2, page 3

R2 v1 2026-06-23T12:22:34.572Z