Principe de Hasse pour les intersections de deux quadriques

Principe local global pour les espaces linéaires sur les intersections de deux quadriques

In arXiv:1410.5671, Jahnel and Loughran prove the local global principle for existence of linear spaces of dimension $r$ on smooth complete intersections of two quadrics in projective space of dimension $2r+2$. We present an alternative proof of a slightly more general result. ----- Dans arXiv:1410.5671, Jahnel et Loughran établissent un principe local-global pour l'existence d'espaces linéaires de dimension $r$ dans les intersections complètes lisses de deux quadriques dans un espace projectif de dimension $2r+2$. On donne une démonstration alternative d'un résultat un peu plus général.

Intersections de deux quadriques et pinceaux de courbes de genre 1

This research monograph focuses on the arithmetic, over number fields, of surfaces fibred into curves of genus 1 over the projective line, and of intersections of two quadrics in projective space. The first half takes up and develops further the technique initiated by Swinnerton-Dyer in 1993, and later generalised by Colliot-Thélène, Skorobogatov and Swinnerton-Dyer, for studying rational points on pencils of curves of genus 1. The second half, which builds upon the first, is devoted to quartic del Pezzo surfaces and to higher-dimensional intersections of two quadrics. Conditionally on two wel…

回顾两个二次曲面交的算术，附 A. Kuznetsov 撰写的附录

Retour sur l'arithmétique des intersections de deux quadriques, avec un appendice par A. Kuznestov

本文综合 Lichtenbaum 与 Salberger 的结果，推广两个二次曲面交上二次点存在性的结论，并重新证明或另证 Heath-Brown 及 Iyer–Parimala 的 Hasse 与局部—整体原理定理。

Dualité et principe local-global sur des corps locaux de dimension 2

Let $k$ be an algebraically closed field, a finite field or a $p$-adic field. Let $K_0=k((x,y))$ be the field of Laurent series in two variables over $k$. We define Tate-Shafarevich groups of a commutative group scheme over $K_0$ via cohomology classes locally trivial at each completion of $K_0$ coming from a codimension 1 point of $\text{Spec}\; k[[x,y]]$. We establish duality theorems between Tate-Shafarevich groups for finite groups schemes and for tori. We apply these results to the study of the obstruction to the local-global principle for $K_0$-torsors under a connected linear algebraic …

Théorèmes de dualité pour les corps de fonctions sur des corps locaux supérieurs et applications arithmétiques

Let $K$ be the function field of a smooth projective curve $X$ over a higher-dimensional local field $k$. We define Tate-Shafarevich groups of a commutative group scheme via cohomology classes locally trivial at each completion of $K$ coming from a closed point of $X$. We establish duality theorems between Tate-Shafarevich groups for finite groups schemes, for tori, for groups of multiplicative type, and even for 2-term complexes of tori. We apply these results to the weak approximation for tori over $K$ and to the study of the obstruction to the local-global principle for $K$-torsors under a …

Zero-cycles and rational points on some surfaces over a global function field

Let F be a finite field of characteristic p. We consider smooth surfaces over F(t) defined by an equation f+tg=0, where f and g are forms of degree d in 4 variables with coefficients in F, with d prime to p. We prove : For such surfaces over F(t), the Brauer-Manin obstruction to the existence of a zero-cycle of degree one is the only obstruction. For d=3 (cubic surfaces), this leads to the same result for rational points. -- Soit F un corps fini de caractéristique p. Pour une surface lisse sur F(t) définie par une équation f+tg=0, où f et g sont deux formes de degré d sur F en 4 variables, ave…