{ "id": "2406.15614", "version": "v1", "published": "2024-06-21T19:29:46.000Z", "updated": "2024-06-21T19:29:46.000Z", "title": "Duplicated Steiner triple systems with self-orthogonal near resolutions", "authors": [ "Peter J. Dukes", "Esther R. Lamken" ], "categories": [ "math.CO" ], "abstract": "A Steiner triple system, STS$(v)$, is a family of $3$-subsets (blocks) of a set of $v$ elements such that any two elements occur together in precisely one block. A collection of triples consisting of two copies of each block of an STS is called a duplicated Steiner triple system, DSTS. A resolvable (or near resolvable) DSTS is called self-orthogonal if every pair of distinct classes in the resolution has at most one block in common. We provide several methods to construct self-orthogonal near resolvable DSTS and settle the existence of such designs for all values of $v$ with only four possible exceptions. This addresses a recent question of Bryant, Davies and Neubecker.", "revisions": [ { "version": "v1", "updated": "2024-06-21T19:29:46.000Z" } ], "analyses": { "subjects": [ "05B07", "05B15" ], "keywords": [ "duplicated steiner triple system", "resolution", "elements occur", "distinct classes", "construct self-orthogonal" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }