{ "id": "2208.14773", "version": "v1", "published": "2022-08-31T11:16:17.000Z", "updated": "2022-08-31T11:16:17.000Z", "title": "Blocking subspaces with points and hyperplanes", "authors": [ "Sam Adriaensen", "Maarten De Boeck", "Lins Denaux" ], "comment": "7 pages", "categories": [ "math.CO" ], "abstract": "In this paper, we characterise the smallest sets $B$ consisting of points and hyperplanes in $\\text{PG}(n,q)$, such that each $k$-space is incident with at least one element of $B$. If $k > \\frac {n-1} 2$, then the smallest construction consists only of points. Dually, if $k < \\frac{n-1}2$, the smallest example consists only of hyperplanes. However, if $k = \\frac{n-1}2$, then there exist sets containing both points and hyperplanes, which are smaller than any blocking set containing only points or only hyperplanes.", "revisions": [ { "version": "v1", "updated": "2022-08-31T11:16:17.000Z" } ], "analyses": { "subjects": [ "05B25", "51E21" ], "keywords": [ "hyperplanes", "blocking subspaces", "smallest example consists", "smallest construction consists", "smallest sets" ], "note": { "typesetting": "TeX", "pages": 7, "language": "en", "license": "arXiv", "status": "editable" } } }