1 Superconvergent discontinuous Galerkin methods for second-order elliptic problems / A multiscale finite element method for partial differential equations posed in domains with rough boundaries / Alexandre L. Madureira 35 Convergence and optimality of adaptive mixed finite element methods / 79 Overlapping additive Schwarz preconditioners for elliptic PDEs… (More)
We present an algorithm for computing discriminants and prime ideal decomposition in number fields. The algorithm is a refinement of a p-adic factorization method based on Newton polygons of higher order. The running-time and memory requirements of the algorithm appear to be very good: for a given prime number p, it computes the p-valuation of the… (More)
We develop a theory of arithmetic Newton polygons of higher order, that provides the factorization of a separable polynomial over a p-adic field, together with relevant arithmetic information about the fields generated by the irreducible factors. This carries out a program suggested by Ø. Ore. As an application, we obtain fast algorithms to compute… (More)
Let p be a prime number. We present an algorithm that computes p-integral bases in number fields. The algorithm is obtained as a by-product of a p-adic factorization method based on Newton polygons of higher order. The running-time of the algorithm appears to be very good: it computes the 2-integral basis of a number field of degree 1152 in a few seconds.
We propose a solution to the hyperelliptic Schottky problem, based on the use of Jacobian Nullwerte and symmetric models for hyperelliptic curves. Both ingredients are interesting on its own, since the first provide period matrices which can be geometrically described, and the second have remarkable arithmetic properties.
We give a closed formula for recovering a non-hyperelliptic genus three curve from its period matrix, and derive some identities between Jacobian Nullwerte in dimension three.
We introduce our package +Ideals for Magma, designed to perform the basic tasks related to ideals in number fields without pre-computing integral bases. It is based on Montes algorithm and a number of local techniques that we have developed in a series of papers in the last years.
We give a method for finding rational equations of genus 2 curves whose jacobians are abelian varieties A f attached by Shimura to normalized newforms f ∈ S2(Γ0(N)). We present all the curves corresponding to principally polarized surfaces A f for N ≤ 500.
Let K be the number field determined by a monic irreducible polynomial f (x) with integer coefficients. In previous papers we parameterized the prime ideals of K in terms of certain invariants attached to Newton polygons of higher order of f (x). In this paper we show how to carry out the basic operations on fractional ideals of K in terms of these… (More)
Let f (x) be a separable polynomial over a local field. Montes algorithm computes certain approximations to the different irreducible factors of f (x), with strong arithmetic properties. In this paper we develop an algorithm to improve any one of these approximations , till a prescribed precision is attained. The most natural application of this "… (More)