We develop a theory of arithmetic Newton polygons of higher\ud order, that provides the factorization of a separable polynomial over a p-adic\ud eld, together with relevant arithmetic information about the elds generated\ud by the irreducible factors. This carries out a program suggested by . Ore.\ud As an application, we obtain fast algorithms to compute discriminants, prime\ud ideal decomposition and integral bases of number elds.Postprint (author’s final draft

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 discriminant and the factorization of p in a number field of degree 1000 in a few seconds, in a personal computer.

Abstract. Let K be a field equipped with a discrete valuation v. In a pioneering work, MacLane determined all valuations on K(x) extending v. His work was recently reviewed and generalized by Vaquié, by using the graded algebra of a valuation. We extend Vaquié's approach by studying residual ideals of the graded algebra as an abstract counterpart of certain residual polynomials which play a key role in the computational applications of the theory. As a consequence, we determine the structure of the graded algebra of the discrete valuations on K(x) and we show how these valuations may be used to parameterize irreducible polynomials over local fields up to Okutsu equivalence.

Abstract. Let A be a Dedekind domain whose field of fractions K is a global field. Let p be a non-zero prime ideal of A, and Kp the completion of K at p. The Montes algorithm factorizes a monic irreducible separable polynomial f (x) ∈ A[x] over Kp, and it provides essential arithmetic information about the finite extensions of Kp determined by the different irreducible factors. In particular, it can be used to compute a p-integral basis of the extension of K determined by f (x). In this paper we present a new and faster method to compute p-integral bases, based on the use of the quotients of certain divisions with remainder of f (x) that occur along the flow of the Montes algorithm.