{ "id": "1407.6945", "version": "v2", "published": "2014-07-25T15:45:49.000Z", "updated": "2014-08-20T15:24:30.000Z", "title": "Low degree hypersurfaces of projective toric varieties defined over a $C_1$ field have a rational point", "authors": [ "Robin Guilbot" ], "comment": "46 pages. This is the long version of the article, with quite a lot of preliminaries aimed at non (toric) geometers. Changes from v1 : Statement and proof of the core theorem simplified, section about decomposition of toric rational contractions removed + minor corrections", "categories": [ "math.AG", "math.NT" ], "abstract": "Quasi algebraically closed fields, or $C_1$ fields, are defined in terms of a low degree condition. Namely, the field $K$ is $C_1$ if every degree $d$ hypersurface of the projective space $\\mathbb{P}_K^n$ contains a $K$-point as soon as $d\\leq n$. In this article we define a notion of low toric degree generalizing this condition for hypersurfaces of simplicial projective split toric varieties. This allows us to prove a particular case of the $C_1$ conjecture of Koll\\'{a}r, Lang and Manin : any smooth separably rationally connected variety that can be embedded as such a hypersurface over a $C_1$ field has a rational point. Our results are based on the fact that the ambient toric varieties are Mori Dream Spaces : they are naturally endowed with homogeneous coordinates and their Minimal Model Program works in all cases.", "revisions": [ { "version": "v1", "updated": "2014-07-25T15:45:49.000Z", "abstract": "Quasi algebraically closed fields, or $C_1$ fields, are defined in terms of a low degree condition. Namely, the field $K$ is $C_1$ if every degree $d$ hypersurface of the projective space $\\mathbb{P}_K^n$ contains a $K$-point as soon as $d\\leq n$. In this article we define a notion of low toric degree generalizing this condition for hypersurfaces of simplicial projective split toric varieties. This allows us to prove a particular case of the $C_1$ conjecture of Koll\\'ar, Lang and Manin : any smooth separably rationally connected variety that can be embedded as such a hypersurface over a $C_1$ field has a rational point. Our results are based on the fact that the ambient toric varieties are Mori Dream Spaces : they are naturally endowed with homogeneous coordinates and their Minimal Model Program works in all cases.", "comment": "50 pages. This is the long version of the article, with quite a lot of preliminaries aimed at non (toric) geometers", "journal": null, "doi": null }, { "version": "v2", "updated": "2014-08-20T15:24:30.000Z" } ], "analyses": { "subjects": [ "14M25", "11G99", "14G05", "14E30" ], "keywords": [ "projective toric varieties", "low degree hypersurfaces", "rational point", "projective split toric varieties", "separably rationally connected variety" ], "note": { "typesetting": "TeX", "pages": 46, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2014arXiv1407.6945G" } } }