### Abstract

Let S be a smooth cubic surface over a finite field
_{q}. It is known that #S(
_{q}) = 1 + aq + q
^{2} for some a ϵ {-2, -1, 0, 1, 2, 3, 4, 5, 7}. Serre has asked which values of a can arise for a given q. Building on special cases treated by Swinnerton-Dyer, we give a complete answer to this question. We also answer the analogous question for other del Pezzo surfaces, and consider the inverse Galois problem for del Pezzo surfaces over finite fields. Finally we give a corrected version of Manin's and Swinnerton-Dyer's tables on cubic surfaces over finite fields.

Original language | English |
---|---|

Pages (from-to) | 35-60 |

Number of pages | 26 |

Journal | Mathematical Proceedings of the Cambridge Philosophical Society |

Volume | 167 |

Issue number | 1 |

Early online date | 10 Apr 2018 |

DOIs | |

Publication status | Published - 1 Jul 2019 |

### ASJC Scopus subject areas

- Mathematics(all)

## Cite this

Banwait, B., Fité, F., & Loughran, D. (2019). Del Pezzo surfaces over finite fields and their Frobenius traces.

*Mathematical Proceedings of the Cambridge Philosophical Society*,*167*(1), 35-60. https://doi.org/10.1017/S0305004118000166