{ "id": "1911.09457", "version": "v1", "published": "2019-11-21T13:19:03.000Z", "updated": "2019-11-21T13:19:03.000Z", "title": "Secant varieties of non-expected dimension on algebraic curves", "authors": [ "Mara Ungureanu" ], "comment": "17 pages. Comments welcome", "categories": [ "math.AG" ], "abstract": "The aim of this paper is to exhibit some surprising examples of secant varieties on a general curve that are empty despite their expected dimension being non-negative. We do so by reformulating the problem in terms of refined de Jonqui\\`eres divisors, that is divisors with prescribed multiplicities and dimensions on the curve. Our examples occur via the study of the dimension theory of refined de Jonqui\\`eres divisors in some relevant cases and degeneration arguments.", "revisions": [ { "version": "v1", "updated": "2019-11-21T13:19:03.000Z" } ], "analyses": { "keywords": [ "secant varieties", "algebraic curves", "non-expected dimension", "general curve", "empty despite" ], "note": { "typesetting": "TeX", "pages": 17, "language": "en", "license": "arXiv", "status": "editable" } } }