English

On the image of a curve in a normal surface by a plane projection

Algebraic Geometry 2024-12-19 v1

Abstract

We consider a finite analytic morphism φ=(f,g)\varphi =(f,g) defined from a complex analytic normal surface (Z,z)(Z,z) to C2{\mathbb C}^2. We describe the topology of the image by φ\varphi of a reduced curve on (Z,z)(Z,z) by means of iterated pencils defined recursively for each branch of the curve from the initial one f,g\langle f,g \rangle. This result generalizes the one obtained in a previous paper for the case in which (Z,z)(Z,z) is smooth and the curve irreducible. As a consequence of the methods we can describe also the topological type of the discriminant curve of φ\varphi, in particular the topological type of each branch of the discriminant can be obtained from the map without the previous knowledge of the critical locus.

Keywords

Cite

@article{arxiv.2412.13970,
  title  = {On the image of a curve in a normal surface by a plane projection},
  author = {F. Delgado and H. Maugendre},
  journal= {arXiv preprint arXiv:2412.13970},
  year   = {2024}
}

Comments

20 pages, 1 figure