English

Analytic normal forms and inverse problems for unfoldings of 2-dimensional saddle-nodes with analytic center manifold

Dynamical Systems 2018-10-12 v1

Abstract

We give normal forms for generic k-dimensional parametric families (Zε)ε(Z_\varepsilon)_\varepsilon of germs of holomorphic vector fields near 0C20\in\mathbb{C}^2 unfolding a saddle-node singularity Z0Z_0, under the condition that there exists a family of invariant analytic curves unfolding the weak separatrix of Z0Z_0. These normal forms provide a moduli space for these parametric families. In our former 2008 paper, a modulus of a family was given as the unfolding of the Martinet-Ramis modulus, but the realization part was missing. We solve the realization problem in that partial case and show the equivalence between the two presentations of the moduli space. Finally, we completely characterize the families which have a modulus depending analytically on the parameter. We provide an application of the result in the field of non-linear, parameterized differential Galois theory.

Keywords

Cite

@article{arxiv.1810.04890,
  title  = {Analytic normal forms and inverse problems for unfoldings of 2-dimensional saddle-nodes with analytic center manifold},
  author = {C. Rousseau and Loïc Jean Dit Teyssier},
  journal= {arXiv preprint arXiv:1810.04890},
  year   = {2018}
}

Comments

Annales Scientifiques de l'{\'E}cole Normale Sup{\'e}rieure, Elsevier Masson, In press