PreprintCC BY 4.0arXiv
HJ numbers revisited
Abstract
We improve the bounds on the Hales-Jewett numbers to a tower of exponentiations. Earlier it was WaW (that is, iterations of towers which are themselves iterated exponentiations). We improve the inductive step there (induction on the size of the alphabet, |Λ|) to 2-exponentiations, instead of towers. In the longer work in typing, (A) We present this inductive step as a partition theorem in its own right; (but in this preliminary version we make it just serve the bound on HJ numbers). (B) We shall deal with the density version of Hales-Jewett with similar bound. We are also dealing with the Graham-Rothschild Theorem and the Affine Ramsey Theorem and the polynomial case, and give background.
Related
BibTeX
@misc{shelah2026numbers,
title = {{HJ numbers revisited}},
author = {Saharon Shelah},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2607.14732},
eprint = {2607.14732},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2607.14732},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - HJ numbers revisited
AU - Saharon Shelah
PY - 2026
DA - 2026/10/15
PB - arXiv
DO - 10.48550/arxiv.2607.14732
UR - https://arxiv.org/abs/2607.14732
AB - We improve the bounds on the Hales-Jewett numbers to a tower of exponentiations. Earlier it was WaW (that is, iterations of towers which are themselves iterated exponentiations). We improve the inductive step there (induction on the size of the alphabet, |Λ|) to 2-exponentiations, instead of towers. In the longer work in typing, (A) We present this inductive step as a partition theorem in its own right; (but in this preliminary version we make it just serve the bound on HJ numbers). (B) We shall deal with the density version of Hales-Jewett with similar bound. We are also dealing with the Graham-Rothschild Theorem and the Affine Ramsey Theorem and the polynomial case, and give background.
ER -