Fundamental groups of some special quadric arrangements

Abstract

In this work we obtain presentations of fundamental groups of the complements of three families of quadric arrangements in ${\mathbb{P}}^2$. The first arrangement is a union of $n$ quadrics, which are tangent to each other at two common points. The second arrangement is composed of $n$ quadrics which are tangent to each other at one common point. The third arrangement is composed of $n$ quadrics, $n-1$ of them are tangent to the $n$'th one and each one of the $n-1$ quadrics is transversal to the other $n-2$ ones.

21 pages, 12 main figures, appears in Revista Mathematicae