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arXiv · 1606.07242

Holomorphic normal form of nonlinear perturbations of nilpotent vector fields

Laurent Stolovitch·Freek Verstringe
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Abstract

We consider germs of holomorphic vector fields at a fixed point having a nilpotent linear part at that point, in dimension $n \geq 3$. Based on Belitskii's work, we know that such a vector field is formally conjugate to a (formal) normal form. We give a condition on that normal form which ensure that the normalizing transformation is holomorphic at the fixed point. We shall show that this sufficient condition is a nilpotent version of Bruno's condition (A). In dimension 2, no condition is required since, according to Str{\'o}zyna- Zoladek, each such germ is holomorphically conjugate to a Takens normal form. Our proof is based on Newton's method and $\frak{sl}\_2(\Bbb C)$-representations.

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Laurent Stolovitch, Freek Verstringe. 2016-06-23. Holomorphic normal form of nonlinear perturbations of nilpotent vector fields. https://doi.org/10.1134/s1560354716040031

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