arXiv subjects
Publications and source records attributed to Alcides Lins Neto.
In this paper, we study the Gauss map of a holomorphic codimension one foliation on the projective space $\mathbb{P}^n$, $n\ge 2$, mainly the case $n=3$. Among other things, we will investigate the case where the Gauss map is birational.
We study the $p$-tuples of holomorphic vector fields $(X_1,X_2,\ldots,X_p)$ satisfying the barycentric property $\displaystyle\sum_k\exp tX_k=p\cdot\mathrm{id}$, where $\exp tX$ denotes the flow of $X$.
Given a holomorphic singular foliation $\fa$ of $(\C^n,0)$ we define $Iso(\fa)$ as the group of germs of biholomorphisms on $(\C^n,0)$ preserving $\fa$: $Iso(\fa)=\{Φ\in Diff(\C^n,0)\,|\,Φ^*(\fa)=\fa\}$. The normal subgroup of $Iso(\fa)$, of biholomorphisms sending each leaf of $\fa$ into itself, will be denoted as $Fix(\fa)$. The corresponding groups of formal biholomorphisms will be denoted as $\wh{Iso}(\fa)$ and $\wh{Fix}(\fa)$, respectively. The purpose of this paper will be to study the quotients $Iso(\fa)/Fix(\fa)$ and $\wh{Fix}(\fa)/\wh{Fix}(\fa)$, mainly in the case of codimension one foliation.
In the main result of this paper we prove that a codimension one foliation of $\mathbb{P}^n$, which is locally a product near every point of some codimension two component of the singular set, has a Kupka component. In particular, we obtain a generalization of a known result of Calvo Andrade and Brunella about foliations with a Kupka component.
We prove that foliations on the projective plane admitting a Liouvillian first integral but not admitting a rational first integral always have invariant algebraic curves of degree bounded by a function of the degree of the foliation. We establish, for the same class of foliations, the existence of a bound for the degree of the simplest integrating factor depending only on the degree of the foliation and on the nature of its singularities. We also prove the existence of invariant algebraic curves of small degree for foliations with rational first integral and intermediate Kodaira dimension.
The purpose of this paper is to study singular holomorphic foliations of arbitrary codimension defined by logarithmic forms on projective spaces.
This paper is devoted to the study of codimension two holomorphic foliations and distributions. We prove the stability of complete intersection of codimension two distributions and foliations in the local case. Converserly we show the existence of codimension two foliations which are not contained in any codimension one foliation. We study problems related to the singular locus and we classify homogeneous foliations of small degree.
Nous décrivons les singularités de feuilletages holomorphes dicritiques de petite multiplicité en dimension $3$. En particulier nous relions l'existence de déformations et de déploiements non triviaux à des problèmes d'intégrabilité liouvillienne. We describe the singularities of dicritical holomorphic foliations of small multiplicity in dimension $3$. In particular we connect the existence of non trivial deformations and deployments to problems of liouvillian integrability.
Let F be a codimension one singular holomorphic foliation on a compact complex manifold M. Assume that there exists a meromorphic vector field X on M generically transversal to F. Then, we prove that F is the meromorphic pull-back of an algebraic foliation on an algebraic manifold N, or F is transversely projective outside a compact hypersurface, improving our previous work (see version 1). Such a vector field insures the existence of a global meromorphic Godbillon-Vey sequence for the foliation F. We derive sufficient conditions on this sequence insuring such alternative. For instance, if there exists a finite Godbillon-Vey sequence or if the Godbillon-Vey invariant is zero, then either F is the pull-back of a foliation on a surface, or F is transversely projective. We illustrate these results with many examples.