We consider Thue equations of the form , and assuming the truth of the abc-conjecture, we show that almost all locally soluble Thue equations of degree at least three violate the Hasse principle. A similar conclusion holds true for Fermat equations of degree at least six.
On construit des courbes elliptiques sur de rang au moins 3, avec un sous-groupe de torsion non trivial. Par spécialisation, des courbes elliptiques de rang 5 et 6 sur sont obtenues.
Let be a number field. Let be a finite set of places of containing all the archimedean ones. Let be the ring of -integers of . In the present paper we consider endomorphisms of of degree , defined over , with good reduction outside . We prove that there exist only finitely many such endomorphisms, up to conjugation by , admitting a periodic point in of order . Also, all but finitely many classes with a periodic point in of order are parametrized by an irreducible curve.
We derive a simple formula for the action of a finite crystallographic Coxeter group on the cohomology of its associated complex toric variety, using the method of counting rational points over finite fields, and the Hodge structure of the cohomology. Various applications are given, including the determination of the graded multiplicity of the reflection representation.
Let be a compact subanalytic surface. This paper shows that, in a suitable sense, there are very few rational points of that do not lie on some connected semialgebraic curve contained in .
This is an extended version of an invited lecture I gave at the Journées Arithmétiques in St. Étienne in July 2009.We discuss the state of the art regarding the problem of finding the set of rational points on a (smooth projective) geometrically integral curve over . The focus is on practical aspects of this problem in the case that the genus of is at least , and therefore the set of rational points is finite.