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Liliana Puchuri

Publications and source records attributed to Liliana Puchuri.

6 recordsLinked to original sources
arXiv2026

Explicit integration, birational models and symmetries of Lins Neto's exceptional families of foliations

In 2002, Lins Neto introduced three remarkable one-parameter families of holomorphic foliations by curves on the complex projective plane, of degrees two, three, and four, whose properties established that the general form of the Poincaré Problem had no solution. These foliations are known to be birationally equivalent to certain quotients of linear foliations on abelian surfaces. We give explicit formulas for these birational equivalences, obtaining, in particular, parametrizations of the leaves of the foliations. For the families of degrees three and four, we determine explicit generators for the groups of birational transformations of the projective plane preserving them. For foliations in these families admitting a rational first integral, that is, for those whose parameter is an Eisenstein rational, we give a complete description of the nature and position of the singular points of a generic integral curve, and we present an algorithm that computes the rational first integral explicitly. Lins Neto's foliations can also be defined over algebraically closed fields of positive characteristic, and, in this setting, we characterize those that are algebraically integrable. Finally, we study the integrability of the reductions to fields of positive characteristic of some of the non-integrable foliations in the complex family.

math.AG↗
arXiv2024

Negative Curves and Elliptic Fibrations on a Special Rational Surface

The blown up complex projective plane in the twelve triple points of the dual Hesse arrangement has an infinite number of irreducible rational curves of self-intersection $-1$, for short, $(-1)$-curves. In the preprint version of [Dumnicki, 2019], T. Szemberg et alii tried to keep track of plane rational curves which produce $(-1)$-curves, by applying successively to a straight line compositions taken from three different quadratic Cremona maps preserving the dual Hesse arrangement, in such a way as to produce a diagram of bifurcations. The symmetric aspect of the degrees of curves encoded in the entries of the diagram motivated them to propose the problem of to give a closed formula for the degree of the rational curve at the entry $a_{i,j}$. We solved this problem for a slightly different diagram of bifurcations of the same Cremona maps, which recover and extends the data on degrees of the original diagram. We also are able to describe the position and multiplicites of singularities of each rational curve encoded in the diagram, as well as their equations (implemented in Python and Singular softwares). Our idea is to embed the plane rational curves as components of special elements of elliptic pencils, then apply a closed formula for the degrees of the generic curves of the elliptic pencils of [Puchuri, 2013], and, from this, extract the data of the rational curves on each entry of the diagram.

math.AG↗
arXiv2024

Effective Integrability of Lins Neto's Family of Foliations

A. Lins Neto presented in [Lins-Neto,2002] a $1$-dimensional family of degree four foliations on the complex projective plane $\mathcal{F}_{t \in \overline{\mathbb{C}}}$ with non-degenerate singularities of fixed analytic type, whose set of parameters $t$ for which $\mathcal{F}_t$ is an elliptic pencil is dense and countable. In [McQuillan,2001] and [Guillot,2002], M. McQuillan and A. Guillot showed that the family lifts to linear foliations on the abelian surface $E \times E$, where $E = \mathbb{C}/Γ$, $Γ= < 1 , τ>$ and $τ$ is a primitive 3rd root of unity, the parameters for which $\mathcal{F}_t$ are elliptic pencils being $t\in \mathbb{Q}(τ) \cup {\infty}$. In [Puchuri,2013], the second author gave a closed formula for the degree of the elliptic curves of $\mathcal{F}_t$ a function of $t \in \mathbb{Q}(τ)$. In this work we determine degree, positions and multiplicities of singularities of the elliptic curves of $\mathcal{F}_t$, for any given $t \in \mathbb{Z}(τ)$ in algorithmical way implemented in Python. And also we obtain the explicit expressions for the generators of the elliptic pencils, using the Singular software. Our constructions depend on the effect of quadratic Cremona maps on the family of foliations $\mathcal{F}_t$.

math.DS↗
arXiv2021

Foliations on $\mathbb{P}^2$ with only one singular point

In this paper we study holomorphic foliations on $\mathbb{P}^2$ with only one singular point. If the singularity has algebraic multiplicity one, we prove that the foliation has no invariant algebraic curve. We also present several examples of such foliations in degree three.

math.DS↗
arXiv2020

Classification of flat pencils of foliations on compact complex surfaces

Related to the classification of regular foliations in a complex algebraic surface, we address the problem of classifying the complex surfaces which admit a flat pencil of foliations. On this matter, a classification of flat pencils which admit foliations with a first integral of genus one and isolated singularities was done by Lins Neto. In this work, we complement Lins Neto's work, by obtaining the classification of compact complex surfaces which have a pencil with an invariant tangency set.

math.CV↗