{ "id": "2204.08551", "version": "v1", "published": "2022-04-18T20:33:47.000Z", "updated": "2022-04-18T20:33:47.000Z", "title": "Lower bound on the maximal number of rational points on curves over finite fields", "authors": [ "Jonas Bergström", "Everett W. Howe", "Elisa Lorenzo García", "Christophe Ritzenthaler" ], "categories": [ "math.NT", "math.AG" ], "abstract": "For a given genus $g \\geq 1$, we give minimal bounds for the maximal number of rational points on a smooth projective absolutely irreducible curve of genus $g$ over $\\F_q$. As a consequence of Katz-Sarnak theory, we first get for any given $g>0$, any $\\epsilon>0$ and all $q$ large enough, the existence of a curve of genus $g$ over $\\F_q$ with at least $1+q+ (2g-\\epsilon) \\sqrt{q}$ rational points. Then using sums of powers of traces of Frobenius of hyperelliptic curves, we get a lower bound of the form $1+q+1.71 \\sqrt{q}$ valid for $g \\geq 3$ and odd $q \\geq 11$. Finally, explicit constructions of towers of curves improve this result, with a bound of the form $1+q+4 \\sqrt{q} -32$ valid for all $g\\ge 2$ and for all~$q$.", "revisions": [ { "version": "v1", "updated": "2022-04-18T20:33:47.000Z" } ], "analyses": { "keywords": [ "rational points", "maximal number", "lower bound", "finite fields", "explicit constructions" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }