Grégoire Lecerf

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Given a system of polynomial equations and inequations with coefficients in the field of rational numbers, we show how to compute a geometric resolution of the set of common roots of the system over the field of complex numbers. A geometric resolution consists of a primitive element of the algebraic extension defined by the set of roots, its minimal(More)
We present a new probabilistic method for solving systems of polynomial equations and inequations. Our algorithm computes the equidimensional decomposition of the Zariski closure of the solution set of such systems. Each equidimensional component is encoded by a generic fiber, that is a finite set of points obtained from the intersection of the component(More)
It is classical that univariate algebraic functions satisfy linear differential equations with polynomial coefficients. Linear recurrences follow for the coefficients of their power series expansions. We show that the linear differential equation of minimal order has coefficients whose degree is cubic in the degree of the function. We also show that there(More)
Let &fnof;<subscrpt>1</subscrpt>, &#8230; , &fnof;<subscrpt><italic>s</italic></subscrpt> be polynomials in <italic>n</italic> variables over a field of characteristic zero and <italic>d</italic> be the maximum of their total degree. We propose a new probabilistic algorithm for computing a <italic>geometric resolution</italic> of each equidimensional part(More)
UNLABELLED BACKGROUND OBJECTIVE: Femoral offset is supposed to influence the results of hip replacement but little is known about the accurate method of measure and the true effect of offset modifications. MATERIAL AND METHODS This article is a collection of independent anatomic, radiological and clinical works, which purpose is to assess knowledge of the(More)
We present new faster deterministic and probabilistic recombination algorithms to compute the irreducible decomposition of a bivariate polynomial via the classical Hensel lifting technique. For the dense bi-degree polynomial representation, the costs of our recombination algorithms are essentially sub-quadratic.