Weak approximation over function fields
We prove that rationally connected varieties over the function field of a complex curve satisfy weak approximation for places of good reduction.
arXiv subjects
Publications and source records attributed to Yuri Tschinkel.
We prove that rationally connected varieties over the function field of a complex curve satisfy weak approximation for places of good reduction.
We study the arithmetic of certain del Pezzo surfaces of degree 2. We produce examples of Brauer-Manin obstruction to the Hasse principle, coming from 2- and 4-torsion elements in the Brauer group.
We study the structure of abelian subgroups of Galois groups of function fields of surfaces.
We study the distribution of algebraic points on K3 surfaces.
We study the equations of universal torsors on rational surfaces.
We construct examples of elliptic fibrations of orbifold general type (in the sense of Campana) which have no etale covers dominating a variety of general type.
Consider the Fulton-MacPherson configuration space of $n$ points on $¶^1$, which is isomorphic to a certain moduli space of stable maps to $¶^1$. We compute the cone of effective ${\mathfrak S}_n$-invariant divisors on this space. This yields a geometric interpretation of known asymptotic formulas for the number of integral points of bounded height on compactifications of $\SL_2$ in the space of binary forms of degree $n\ge 3$.
We prove rationality results for moduli spaces of elliptic K3 surfaces and elliptic rational surfaces with fixed monodromy groups.
We study analytic properties of height zeta functions of equivariant compactifications of the Heisenberg group.
We construct examples of simply connected nonalgebraic symplectic fourfolds with a prescribed number of nonintersecting symplectic curves with positive self-intersections.
We study correspondences between algebraic curves defined over the separable closure of $\Q$ or $\F_p$.
We compute the effective cone for the moduli space of stable rational curves with at most six marked points.
We prove asymptotic formulas for the number of rational points of bounded height on smooth equivariant compactifications of the affine space. (Nous établissons un développement asymptotique du nombre de points rationnels de hauteur bornée sur les compactifications équivariantes lisses de l'espace affine.)
We study abelian subgroups of Galois groups of function fields.
We construct examples of algebraic surfaces with interesting fundamental groups.
We study the distribution of integral points on log varieties.
This paper is devoted to the estimation of the number of points of bounded height on fibrations in toric varieties over algebraic varieties, generalizing previous work by Strauch and the second author. Under reasonable hypotheses on ``Arakelov L-functions'' of the base, we show how to deduce a good estimate for the open subset of the total space of the unerlying fibration in torus. In passing, we improve drastically the error term for toric varieties themselves, generalizing a theorem by de la Breteche over any number field.
We study monodromy groups of elliptic fibrations over the projective line.