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arXiv · 1402.2616

Un calcul d'anneaux de d\'eformations potentiellement Barsotti--Tate

Xavier Caruso·Agnès David·Ariane Mézard
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Abstract

Let F be an unramified extension of Qp. The first aim of this work is to develop a purely local method to compute the potentially Barsotti-Tate deformations rings with tame Galois type of irreducible two-dimensional representations of the absolute Galois group of F. We then apply our method in the particular case where F has degree 2 over Q_p and determine this way almost all these deformations rings. In this particular case, we observe a close relationship between the structure of these deformations rings and the geometry of the associated Kisin variety. As a corollary and still assuming that F has degree 2 over Q_p, we prove, except in two very particular cases, a conjecture of Kisin which predicts that intrinsic Galois multiplicities are all equal to 0 or 1.

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Xavier Caruso, Agnès David, Ariane Mézard. 2014-02-11. Un calcul d'anneaux de d\'eformations potentiellement Barsotti--Tate. https://arxiv.org/abs/1402.2616

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