{ "id": "1508.00830", "version": "v1", "published": "2015-08-04T16:52:43.000Z", "updated": "2015-08-04T16:52:43.000Z", "title": "Height bounds on zeros of quadratic forms over $\\overline{\\mathbb Q}$", "authors": [ "Lenny Fukshansky" ], "comment": "23 pages; to appear in Research in Mathematical Sciences. arXiv admin note: substantial text overlap with arXiv:1307.0564", "categories": [ "math.NT" ], "abstract": "In this paper we establish three results on small-height zeros of quadratic polynomials over $\\overline{\\mathbb Q}$. For a single quadratic form in $N \\geq 2$ variables on a subspace of $\\overline{\\mathbb Q}^N$, we prove an upper bound on the height of a smallest nontrivial zero outside of an algebraic set under the assumption that such a zero exists. For a system of $k$ quadratic forms on an $L$-dimensional subspace of $\\overline{\\mathbb Q}^N$, $N \\geq L \\geq \\frac{k(k+1)}{2}+1$, we prove existence of a nontrivial simultaneous small-height zero. For a system of one or two inhomogeneous quadratic and $m$ linear polynomials in $N \\geq m+4$ variables, we obtain upper bounds on the height of a smallest simultaneous zero, if such a zero exists. Our investigation extends previous results on small zeros of quadratic forms, including Cassels' theorem and its various generalizations and contributes to the literature of so-called \"absolute\" Diophantine results with respect to height. All bounds on height are explicit.", "revisions": [ { "version": "v1", "updated": "2015-08-04T16:52:43.000Z" } ], "analyses": { "subjects": [ "11G50", "11E12", "11E39" ], "keywords": [ "height bounds", "upper bound", "smallest nontrivial zero outside", "single quadratic form", "nontrivial simultaneous small-height zero" ], "note": { "typesetting": "TeX", "pages": 23, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2015arXiv150800830F" } } }