{ "id": "2109.03929", "version": "v1", "published": "2021-09-08T21:02:57.000Z", "updated": "2021-09-08T21:02:57.000Z", "title": "Independence inheritance and Diophantine approximation for systems of linear forms", "authors": [ "Demi Allen", "Felipe A. Ramirez" ], "comment": "27 pages, 1 figure", "categories": [ "math.NT" ], "abstract": "The classical Khintchine-Groshev theorem is a generalization of Khintchine's theorem on simultaneous Diophantine approximation, from approximation of points in $\\mathbb R^m$ to approximation of systems of linear forms in $\\mathbb R^{nm}$. In this paper, we present an inhomogeneous version of the Khintchine-Groshev theorem which does not carry a monotonicity assumption when $nm>2$. Our results bring the inhomogeneous theory almost in line with the homogeneous theory, where it is known by a result of Beresnevich and Velani (2010) that monotonicity is not required when $nm>1$. That result resolved a conjecture of Beresnevich, Bernik, Dodson, and Velani (2009), and our work resolves almost every case of the natural inhomogeneous generalization of that conjecture. Regarding the two cases where $nm=2$, we are able to remove monotonicity by assuming extra divergence of a measure sum, akin to a linear forms version of the Duffin-Schaeffer conjecture. When $nm=1$ it is known by work of Duffin and Schaeffer (1941) that the monotonicity assumption cannot be dropped. The key new result is an independence inheritance phenomenon; the underlying idea is that the sets involved in the $((n+k)\\times m)$-dimensional Khintchine-Groshev theorem ($k\\geq 0$) are always $k$-levels more probabilistically independent than the sets involved the $(n\\times m)$-dimensional theorem. Hence, it is shown that Khintchine's theorem itself underpins the Khintchine-Groshev theory.", "revisions": [ { "version": "v1", "updated": "2021-09-08T21:02:57.000Z" } ], "analyses": { "keywords": [ "diophantine approximation", "khintchines theorem", "monotonicity assumption", "dimensional khintchine-groshev theorem", "independence inheritance phenomenon" ], "note": { "typesetting": "TeX", "pages": 27, "language": "en", "license": "arXiv", "status": "editable" } } }