On a Theorem by Bezboruah & Shepherdson
Logic
2026-05-06 v2
Abstract
We discuss an incompleteness result proven by Bezboruah and Shepherdson. This result tells us that the weak theory does not prove the consistency of any theory (under certain assumptions explained in the paper). Kreisel argued that such a result is not meaningful. We discuss Kreisel's objection and conclude that his argument does not hold water. We compare Pudl\'ak's extension of the Second Incompleteness Theorem with the Bezboruah-Sheperdson Theorem. Finally, we reprove the Bezboruah-Sheperdson Theorem for a sequence coding based on an insight of Nielsen and Markov.
Cite
@article{arxiv.2603.06068,
title = {On a Theorem by Bezboruah & Shepherdson},
author = {Albert Visser},
journal= {arXiv preprint arXiv:2603.06068},
year = {2026}
}
Comments
A mistake towards the end of the paper was repaired. The correct result is now given in Theorem 4.6