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  • This session has been presented January 23, 2004.

Description

  • Speaker

    Bas Edixhoven - Leiden University

En commençant par un calcul explicite sur une courbe elliptique, j'expliquerai ma stratégie pour calculer le corps de définition d'un point de torsion d'une jacobienne d'une courbe de genre quelconque. En gros, cette stratégie consiste à calculer le polynôme minimal d'une coordonnée d'un tel point par une approximation (complexe ou p-adique) avec une précision suffisante. J'expliquerai comment la théorie d'Arakelov doit fournir une borne raisonnable pour la précision requise. Comme application, j'espère obtenir un algorithme pour calculer tau(p), avec tau la fonction de Ramanujan et p premier, en temps polynomial en le logarithme de p. Je dirai aussi ce qui reste à faire.

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