{ "id": "2310.18873", "version": "v1", "published": "2023-10-29T02:15:51.000Z", "updated": "2023-10-29T02:15:51.000Z", "title": "Combined exponential patterns in multiplicative $IP^{\\star}$ sets", "authors": [ "Pintu Debnath", "Sayan Goswami" ], "categories": [ "math.CO" ], "abstract": "$IP$ sets play fundamental role in arithmetic Ramsey theory. A set is called an additive $IP$ set if it is of the form $FS\\left(\\langle x_{n}\\rangle_{n\\in \\mathbb{N}}\\right)=\\left\\{ \\sum_{t\\in H}x_{t}:H\\right.$ is a nonempty finite subset of $\\left.\\mathbb{N}\\right\\}$, whereas it is called a multiplicative $IP$ set if it is of the form $FP\\left(\\langle x_{n}\\rangle_{n\\in \\mathbb{N}}\\right)=\\left\\{ \\prod_{t\\in H}x_{t}:H\\right.$ is a nonempty finite subset of $\\left. \\mathbb{N}\\right\\}$ for some injective sequence $\\langle x_{n}\\rangle_{n\\in \\mathbb{N}}.$ An additive $IP^{\\star}$ (resp. multiplicative $IP^{\\star}$) set is a set which intersects every additive $IP$ set (resp. multiplicative $IP$ set). In \\cite{key-1}, V. Bergelson and N. Hindman studied how rich additive $IP^{\\star}$ sets are. They proved additive $IP^{\\star}$ sets ($AIP^{\\star}$ in short) contain finite sums and finite products of a single sequence. An analogous study was made by A. Sisto in\\cite{key-3}, where he proved that multiplicative $IP^{\\star}$ sets ($MIP^{\\star}$ in short) contain exponential tower\\footnote{will be defined later} and finite product of a single sequence. However exponential patterns can be defined in two different ways. In this article we will prove that $MIP^{\\star}$ sets contain two different exponential patterns and finite product of a single sequence. This immediately improves the result of A. Sisto. We also construct a $MIP^\\star$ set, not arising from the recurrence of measurable dynamical systems. Throughout our work we will use the machinery of the algebra of the Stone-\\v{C}ech Compactification of $\\mathbb{N}$.", "revisions": [ { "version": "v1", "updated": "2023-10-29T02:15:51.000Z" } ], "analyses": { "subjects": [ "05D10" ], "keywords": [ "exponential patterns", "finite product", "single sequence", "nonempty finite subset", "multiplicative" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }