An Example of Unirational Surfaces in Characteristic p.
We prove that for any , the curvein is a genus curve violating the Hasse principle. An explicit Weierstrass model for its jacobian is given. The Shafarevich-Tate group of each contains a subgroup isomorphic to .
Si costruiscono famiglie di curve iperellittiche col —rango della varietà jacobiana uguale a zero. La costruzione sfrutta le proprietà elementari dell’operatore di Cartier e delle estensioni -cicliche dei corpi con la caratteristica maggiore di zero.
On démontre que les surfaces cubiques lisses sur les corps de fonctions d’une courbe sur un corps algébriquement clos de caractéristique vérifient l’approximation faible aux places de bonne réduction. La méthode utilisée imite celle employée par Swinnerton-Dyer [10] dans le cas des corps de nombres.
Arakelov invariants of arithmetic surfaces are well known for genus 1 and 2 ([4], [2]). In this note, we study the modular height and the Arakelov self-intersection for a family of curves of genus 3 with many automorphisms:Arakelov calculus involves both analytic and arithmetic computations. We express the periods of the curve in terms of elliptic integrals. The substitutions used in these integrals provide a splitting of the jacobian of as a product of three elliptic curves. Using the corresponding...