{ "id": "2211.02326", "version": "v1", "published": "2022-11-04T09:01:52.000Z", "updated": "2022-11-04T09:01:52.000Z", "title": "Separating rank 3 graphs", "authors": [ "John Bamberg", "Michael Giudici", "Jesse Lansdown", "Gordon F. Royle" ], "categories": [ "math.CO" ], "abstract": "We classify, up to some notoriously hard cases, the rank 3 graphs which fail to meet either the Delsarte or the Hoffman bound. As a consequence, we resolve the question of separation for the corresponding rank 3 primitive groups and give new examples of synchronising, but not $\\mathbb{Q}\\mathrm{I}$, groups of affine type.", "revisions": [ { "version": "v1", "updated": "2022-11-04T09:01:52.000Z" } ], "analyses": { "subjects": [ "05E30", "05C69", "20B15", "05C50", "05E18" ], "keywords": [ "separating rank", "hoffman bound", "affine type", "notoriously hard cases", "consequence" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }