Arithmetic of formal groups and applications I: Universal norm subgroups.
Si est un corps de nombres, on note son anneau d’entiers ; si est une extension galoisienne finie de corps de nombres de groupe de Galois , on appelle base normale de sur toute base de en tant que -module de la forme avec . On démontre dans ce travail un critère d’existence de base normale d’entiers pour les extensions de Kummer de degré premier, qui permet une construction explicite en cas d’existence ; les principaux outils pour la démonstration sont une formule de Fröhlich pour...
Let K = Q(ζp) and let hp be its class number. Kummer showed that p divides hp if and only if p divides the numerator of some Bernoulli number. In this expository note we discuss the generalizations of this type of criterion to totally real fields and quadratic imaginary fields.
In a recent paper we proved that there are at most finitely many complex numbers such that the points and are both torsion on the Legendre elliptic curve defined by . In a sequel we gave a generalization to any two points with coordinates algebraic over the field and even over . Here we reconsider the special case and with complex numbers and .
This is an exposition of the recent work of Bugeaud, Hanrot and Mihăilescu showing that Catalan’s conjecture can be proved without using logarithmic forms and electronic computations.
The subject of the talk is the recent work of Mihăilescu, who proved that the equation has no solutions in non-zero integers and odd primes . Together with the results of Lebesgue (1850) and Ko Chao (1865) this implies the celebratedconjecture of Catalan (1843): the only solution to in integers and is . Before the work of Mihăilescu the most definitive result on Catalan’s problem was due to Tijdeman (1976), who proved that the solutions of Catalan’s equation are bounded by an absolute...