{ "id": "2002.07460", "version": "v1", "published": "2020-02-18T10:00:49.000Z", "updated": "2020-02-18T10:00:49.000Z", "title": "Similarity Isometries of Point Packings", "authors": [ "Jeanine Concepcion H. Arias", "Manuel Joseph C. Loquias" ], "comment": "13 pages, 6 figures", "categories": [ "math.MG", "math.CO" ], "abstract": "A linear isometry $R$ of $\\mathbb{R}^d$ is called a similarity isometry of a lattice $\\Gamma \\subseteq \\mathbb{R}^d$ if there exists a positive real number $\\beta$ such that $\\beta R\\Gamma$ is a sublattice of (finite index in) $\\Gamma$. The set $\\beta R\\Gamma$ is referred to as a similar sublattice of $\\Gamma$. A (crystallographic) point packing generated by a lattice $\\Gamma$ is a union of $\\Gamma$ with finitely many shifted copies of $\\Gamma$. In this study, the notion of similarity isometries is extended to point packings. We provide a characterization for the similarity isometries of point packings and identify the corresponding similar subpackings. Planar examples will be discussed, namely, the $1 \\times 2$ rectangular lattice and the hexagonal packing (or honeycomb lattice). Finally, we also consider similarity isometries of point packings about points different from the origin. In particular, similarity isometries of a certain shifted hexagonal packing will be computed and compared with that of the hexagonal packing.", "revisions": [ { "version": "v1", "updated": "2020-02-18T10:00:49.000Z" } ], "analyses": { "subjects": [ "52C07", "52C05", "11H06", "82D25" ], "keywords": [ "similarity isometry", "point packing", "hexagonal packing", "finite index", "similar sublattice" ], "note": { "typesetting": "TeX", "pages": 13, "language": "en", "license": "arXiv", "status": "editable" } } }