{ "id": "2008.07297", "version": "v1", "published": "2020-08-17T13:27:43.000Z", "updated": "2020-08-17T13:27:43.000Z", "title": "On monochromatic solutions to $x-y=z^2$", "authors": [ "Tom Sanders" ], "comment": "6pp; for Endre Szemeredi's 80th Birthday volume", "journal": "Acta Math. Hungar. 161 (2020), no. 2, 550-556", "doi": "10.1007/s10474-020-01079-6", "categories": [ "math.CO" ], "abstract": "For $k \\in \\mathbb{N}$, write $S(k)$ for the largest natural number such that there is a $k$-colouring of $\\{1,\\dots,S(k)\\}$ with no monochromatic solution to $x-y=z^2$. That $S(k)$ exists is a result of Bergelson, and a simple example shows that $S(k) \\geq 2^{2^{k-1}}$. The purpose of this note is to show that $S(k)\\leq 2^{2^{2^{O(k)}}}$.", "revisions": [ { "version": "v1", "updated": "2020-08-17T13:27:43.000Z" } ], "analyses": { "keywords": [ "monochromatic solution", "largest natural number", "simple example" ], "tags": [ "journal article" ], "publication": { "publisher": "Springer" }, "note": { "typesetting": "TeX", "pages": 6, "language": "en", "license": "arXiv", "status": "editable" } } }