{ "id": "1708.01029", "version": "v1", "published": "2017-08-03T07:23:16.000Z", "updated": "2017-08-03T07:23:16.000Z", "title": "Ranks on the boundaries of secant varieties", "authors": [ "Edoardo Ballico" ], "categories": [ "math.AG" ], "abstract": "In many cases (e.g. for many Segre or Segre embeddings of multiprojective spaces) we prove that a hypersurface of the $b$-secant variety of $X\\subset \\mathbb {P}^r$ has $X$-rank $>b$. We prove it proving that the $X$-rank of a general point of the join of $b-2$ copies of $X$ and the tangential variety of $X$ is $>b$.", "revisions": [ { "version": "v1", "updated": "2017-08-03T07:23:16.000Z" } ], "analyses": { "subjects": [ "14N05", "15A69" ], "keywords": [ "secant variety", "boundaries", "tangential variety", "segre embeddings" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }