The Geometry of the Exceptional Component of Degree Two Foliations on ${\mathbb{P}}^3$

Abstract

We study the exceptional component of the space $\mathbb{F}(2,{\mathbb{P}}^3)$, of codimension-one foliations of degree two on ${\mathbb{P}}^3$. We describe the geometry of its boundary and prove that it has four irreducible components, all of dimension $12$. Three of these components contain a dense subset given by the orbit of a logarithmic foliation of type $(1,1,2)$, while the fourth contains a family of pull-back type foliations from ${\mathbb{P}}^2$ whose orbits have dimension $11$.