PreprintCC BY 4.0arXiv
Resolving Erdős-Ulam Monochromatic Union-Closed Family Conjectures
Abstract
We prove both Erdős-Ulam conjectures on monochromatic union-closed families. Every two-colouring of the subsets of a finite set contains a monochromatic union-closed family whose size grows faster than any fixed power of the size of the set, while suitable colourings admit no monochromatic union-closed family of exponential size. Both results hold for any number of colours and are verified in Lean.
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BibTeX
@misc{bhattacharjee2026resolving,
title = {{Resolving Erdős-Ulam Monochromatic Union-Closed Family Conjectures}},
author = {Deep Bhattacharjee and Priyabrata Mandal and Ushashi Bhattacharya},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.02833},
eprint = {2610.02833},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.02833},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Resolving Erdős-Ulam Monochromatic Union-Closed Family Conjectures
AU - Deep Bhattacharjee
AU - Priyabrata Mandal
AU - Ushashi Bhattacharya
PY - 2026
DA - 2026/10/02
PB - arXiv
DO - 10.48550/arxiv.2610.02833
UR - https://arxiv.org/abs/2610.02833
AB - We prove both Erdős-Ulam conjectures on monochromatic union-closed families. Every two-colouring of the subsets of a finite set contains a monochromatic union-closed family whose size grows faster than any fixed power of the size of the set, while suitable colourings admit no monochromatic union-closed family of exponential size. Both results hold for any number of colours and are verified in Lean.
ER -