{ "id": "2412.04066", "version": "v1", "published": "2024-12-05T11:00:23.000Z", "updated": "2024-12-05T11:00:23.000Z", "title": "A note on infinite versions of $(p,q)$-theorems", "authors": [ "Attila Jung", "Dömötör Pálvölgyi" ], "comment": "A previous version of this work appeared as part of arXiv:2311.15646 (v1 and v2). The main theorem is included there, but the current version provides a clearer presentation and additional applications", "categories": [ "math.CO" ], "abstract": "We prove that fractional Helly and $(p,q)$-theorems imply $(\\aleph_0,q)$-theorems in an entirely abstract setting. We give a plethora of applications, including reproving almost all earlier $(\\aleph_0,q)$-theorems about geometric hypergraphs that were proved recently. Some of the corollaries are new results, for example, we prove that if $\\mathcal{F}$ is an infinite family of convex compact sets in $\\mathbb{R}^d$ and among every $\\aleph_0$ of the sets some $d+1$ contain a point in their intersection with integer coordinates, then all the members of $\\mathcal{F}$ can be hit with finitely many points with integer coordinates.", "revisions": [ { "version": "v1", "updated": "2024-12-05T11:00:23.000Z" } ], "analyses": { "subjects": [ "52A35" ], "keywords": [ "infinite versions", "integer coordinates", "convex compact sets", "geometric hypergraphs", "fractional" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }