{ "id": "2306.04412", "version": "v1", "published": "2023-06-07T13:13:34.000Z", "updated": "2023-06-07T13:13:34.000Z", "title": "Width of convex bodies in hyperbolic space", "authors": [ "Marek Lassak" ], "comment": "13 pages, 6 figures", "categories": [ "math.MG" ], "abstract": "For every hyperplane $H$ supporting a convex body $C$ in the hyperbolic space $\\mathbb{H}^d$ we define the width of $C$ determined by $H$ as the distance between $H$ and a most distant ultraparallel hyperplane supporting $C$. We define bodies of constant width in $\\mathbb{H}^d$ in the standard way as bodies whose all widths are equal. We show that every body of constant width is strictly convex. The minimum width of $C$ over all supporting $H$ is called the thickness $\\Delta (C)$ of $C$. A convex body $R \\subset \\mathbb{H}^d$ is said to be reduced if $\\Delta (Z) < \\Delta (R)$ for every convex body $Z$ properly contained in $R$. We show that regular tetrahedra in $\\mathbb{H}^3$ are not reduced. Similarly as in $\\mathbb{E}^d$, we introduce complete bodies and bodies of constant diameter. They appear to coincide with bodies of constant width of the same diameter.", "revisions": [ { "version": "v1", "updated": "2023-06-07T13:13:34.000Z" } ], "analyses": { "subjects": [ "52A55", "A.0" ], "keywords": [ "convex body", "hyperbolic space", "constant width", "distant ultraparallel hyperplane supporting", "define bodies" ], "note": { "typesetting": "TeX", "pages": 13, "language": "en", "license": "arXiv", "status": "editable" } } }