{ "id": "2106.12756", "version": "v1", "published": "2021-06-24T03:41:18.000Z", "updated": "2021-06-24T03:41:18.000Z", "title": "Roots of the characteristic polynomials of hyperplane arrangements and their restrictions and localizations", "authors": [ "Takuro Abe" ], "comment": "18 pages", "categories": [ "math.CO" ], "abstract": "Terao's factorization theorem shows that if an arrangement is free, then its characteristic polynomial factors into the product of linear polynomials over the integer ring. This is not a necessary condition, but there are not so many non-free arrangements whose characteristic polynomial factors over the integer ring. On the other hand, the localization of a free arrangement is free, and its restriction is in many cases free, thus its characteristic polynomial factors. In this paper, we consider how their integer, or real roots behave.", "revisions": [ { "version": "v1", "updated": "2021-06-24T03:41:18.000Z" } ], "analyses": { "subjects": [ "32S22" ], "keywords": [ "characteristic polynomial factors", "hyperplane arrangements", "restriction", "localization", "real roots behave" ], "note": { "typesetting": "TeX", "pages": 18, "language": "en", "license": "arXiv", "status": "editable" } } }