Point Counting on Non-Hyperelliptic Genus 3 Curves with Automorphism Group $\mathbb{Z} / 2 \mathbb{Z}$ using Monsky-Washnitzer Cohomology Auteur(s): Shieh Y.-D. Chapître d'ouvrage: Algorithmic Arithmetic, Geometry, And Coding Theory, vol. 637 p.173--189 (2015) Ref HAL: hal-01321844_v1 Ref Arxiv: 1603.00566 DOI: 10.1090/conm/637/12757 Ref. & Cit.: NASA ADS Exporter : BibTex | endNote Résumé: We describe an algorithm to compute the zeta function of any non-hyperelliptic genus 3 plane curve $C$ over a finite field with automorphism group $G = \mathbb{Z} / 2 \mathbb{Z}$. This algorithm computes in the Monsky-Washnitzer cohomology of~the curve. Using the relation between the Monsky-Washnitzer cohomology of $C$ and its quotient $E := C/G$, the computation splits into 2 parts: one in a subspace of the Monsky-Washnitzer cohomology and a second which reduces to the point counting on an elliptic curve $E$. The former corresponds to the dimension $2$ abelian surface $\mathrm{ker}(\mathrm{Jac}(C) \rightarrow E)$, on which we can compute with lower precision and with matrices of smaller dimension. Hence we obtain a faster algorithm than working directly on the curve $C$. Commentaires: 17 pages. Published in Algorithmic Arithmetic, Geometry, and Coding Theory, Contemporary Mathematics, vol. 637, Amer. Math. Soc., Providence, RI, 2015, pp. 173-189