Produção Nacional
Revisado por pares
Jorge Vitório Pereira, Luc Pirio,
Codimension one webs are configurations of finitely many codimension one foliations in general position. Much of the classical theory evolved around the concept of abelian relation: a functional equation among the first integrals of the foliations defining the web reminiscent of Abel’s Addition Theorem. The abelian relations of a given web form a finite-dimensional vector space with dimension (the rank of the web) bounded by Castelnuovo number π(n, k) where n is the dimension of the ambient space ...
Tópico(s): DNA and Biological Computing
2009 - Oxford University Press | International Mathematics Research Notices
Produção Nacional
Revisado por pares
Let $\mathcal{F}$ be a holomorphic foliation of general type on $\mathbb{P}^2$ which admits a rational first integral. We provide bounds for the degree of the first integral of $\mathcal{F}$ just in function of the degree and the birational invariants of $\mathcal{F}$ and the geometric genus of a generic leaf. Similar bounds for invariant algebraic curves are also obtained and examples are given showing the necessity of the hypothesis.
Tópico(s): Meromorphic and Entire Functions
2002 - Springer Nature | Mathematische Annalen
Jorge Vitório Pereira, Percy Fernández Sánchez,
We prove that the self-bimeromorphisms group of a foliation of general type on a projective surface is finite.Along the proof we study the structure of arbitrary codimension foliations on projective varieties invariant by an infinite linear algebraic group.
Tópico(s): Advanced Algebra and Geometry
2002 - | Communications in Analysis and Geometry
Fernando Cukierman, Jorge Vitório Pereira,
We show that the set of singular holomorphic foliations of the projective spaces with split tangent sheaf and with good singular set is open in the space of holomorphic foliations. As applications we present a generalization of a result by Camacho-Lins Neto about linear pull-back foliations, we give a criterium for the rigidity of $\mathcal L$-foliations of codimension $k \ge 2$ and prove a conjecture by Cerveau-Deserti about the rigidity of a codimension one $\mathcal L$-foliation of $\mathbb P^4$. These ...
Tópico(s): Algebraic Geometry and Number Theory
2008 - Johns Hopkins University Press | American Journal of Mathematics
Produção Nacional
Revisado por pares
Jorge Vitório Pereira, S. Yuzvinsky,
We study completely reducible fibers of pencils of hypersurfaces on $\mathbb P^n$ and associated codimension one foliations of $\mathbb P^n$. Using methods from theory of foliations we obtain certain upper bounds for the number of these fibers as functions only of $n$. Equivalently this gives upper bounds for the dimensions of resonance varieties of hyperplane arrangements. We obtain similar bounds for the dimensions of the characteristic varieties of the arrangement complements.
Tópico(s): Geometric and Algebraic Topology
2008 - Elsevier BV | Advances in Mathematics
Produção Nacional
Revisado por pares
Charles Favre, Jorge Vitório Pereira,
We give a classification of pairs $${(\mathcal{F}, \phi)}$$ where $${\mathcal{F}}$$ is a holomorphic foliation on a projective surface and $${\phi}$$ is a non-invertible dominant rational map preserving $${\mathcal{F}}$$ .
Tópico(s): Advanced Differential Equations and Dynamical Systems
2010 - Springer Science+Business Media | Mathematische Zeitschrift
Fernando Cukierman, Jorge Vitório Pereira, Israel Vainsencher,
We show that the singular holomorphic foliations induced by dominant quasi-homogeneous rational maps fill out irreducible components of the space ℱ q (r,d) of singular foliations of codimension q and degree d on the complex projective space ℙ r , when 1≤q≤r-2. We study the geometry of these irreducible components. In particular we prove that they are all rational varieties and we compute their projective degrees in several cases.
Tópico(s): Meromorphic and Entire Functions
2010 - Cellule MathDoc/CEDRAM | Annales de la faculté des sciences de Toulouse Mathématiques
Produção Nacional
Revisado por pares
Frank Loray, Jorge Vitório Pereira,
We introduce a notion of normal form for transversely projective structures of singular foliations on complex manifolds. Our first main result says that this normal form exists and is unique when ambient space is two-dimensional. From this result one obtains a natural way to produce invariants for transversely projective foliations on surfaces. Our second main result says that on projective surfaces one can construct singular transversely projective foliations with prescribed monodromy.
Tópico(s): Geometric and Algebraic Topology
2007 - World Scientific | International Journal of Mathematics
Produção Nacional
Revisado por pares
Dominique Cerveau, Alcides Lins Neto, Frank Loray, Jorge Vitório Pereira, Frédéric Touzet,
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 ...
Tópico(s): Algebraic Geometry and Number Theory
2007 - Independent University of Moscow | Moscow Mathematical Journal
Colin Christopher, Jaume Llibre, Jorge Vitório Pereira,
The aim of this paper is to introduce a concrete notion of multiplicity for invariant algebraic curves in polynomial vector fields.In fact, we give several natural definitions and show that they are all equivalent to our main definition, under some "generic" assumptions.In particular, we show that there is a natural equivalence between the algebraic viewpoint (multiplicities defined by extactic curves or exponential factors) and the geometric viewpoint (multiplicities defined by the number of algebraic ...
Tópico(s): Polynomial and algebraic computation
2007 - Mathematical Sciences Publishers | Pacific Journal of Mathematics
Produção Nacional
Revisado por pares
S. C. Coutinho, Jorge Vitório Pereira,
Let X be a smooth complex projective variety of dimension greater than or equal to 2, L an ample line bundle and k ≫ 0 an integer. We prove that a very generic global section of the twisted tangent sheaf gives rise to a foliation of X without any proper algebraic invariant subvarieties of nonzero dimension. As a corollary we obtain a dynamical characterization of ampleness for line bundles over smooth projective surfaces.
Tópico(s): Meromorphic and Entire Functions
2006 - De Gruyter | Journal für die reine und angewandte Mathematik (Crelles Journal)
Produção Nacional
Revisado por pares
We use flat divisors, and canonically associated singular holomorphic foliations, to investigate some of the geometry of compact complex manifolds. The paper is mainly concerned with three distinct problems: the existence of fibrations, the topology of smooth hypersurfaces, and the topological closure of transcendental leaves of foliations.
Tópico(s): Geometric Analysis and Curvature Flows
2005 - American Mathematical Society | Journal of Algebraic Geometry
Produção Nacional
Revisado por pares
Lu�s Gustavo Mendes, Jorge Vitório Pereira,
We describe explicitly holomorphic singular foliations on the projective plane corresponding to natural foliations of Hilbert modular surfaces associated to the field Q. These are concrete models for a very special class of foliations in the recent birational classification of foliations on projective surfaces.
Tópico(s): Geometric Analysis and Curvature Flows
2005 - European Mathematical Society | Commentarii Mathematici Helvetici
Produção Nacional
Revisado por pares
Gaël Cousin, Jorge Vitório Pereira,
We describe the structure of singular transversely affine foliations of codimension one on projective manifolds with zero first Betti number.Our result can be rephrased as a theorem on rank two reducible flat meromorphic connections. 1 Introduction 986 2 Transversely affine foliations 988 2.1 Definition 988 2.2 Interpretation in terms of rational 1-forms 989 2.3 Singular divisor and residues 990 2.4 Examples and first properties 992 2.5 Holonomy 996 2.6 Transversely affine foliations as transversely ...
Tópico(s): Algebraic Geometry and Number Theory
2014 - International Press of Boston | Mathematical Research Letters
Produção Nacional
Revisado por pares
Jorge Vitório Pereira, Frédéric Touzet,
In this paper we aim at the description of foliations having tangent sheaf T F with c 1 (T F) = c 2(T F) = 0 on non-uniruled projective manifolds. We prove that the universal covering of the ambient manifold splits as a product, and that the Zariski closure of a general leaf of F is an Abelian variety. It turns out that the analytic type of the Zariski closures of leaves may vary from leaf to leaf. We discuss how this variation is related to arithmetic properties of the tangent sheaf of the foliation.
Tópico(s): Advanced Algebra and Geometry
2013 - Springer Science+Business Media | Bulletin of the Brazilian Mathematical Society New Series
Produção Nacional
Revisado por pares
David Marìn, Jorge Vitório Pereira,
This paper studies global webs on the projective plane with vanishing curvature.The study is based on an interplay of local and global arguments.The main local ingredient is a criterium for the regularity of the curvature at the neighborhood of a generic point of the discriminant.The main global ingredient, the Legendre transform, is an avatar of classical projective duality in the realm of differential equations.We show that the Legendre transform of what we call reduced convex foliations are webs ...
Tópico(s): Algebraic Geometry and Number Theory
2013 - | Asian Journal of Mathematics
Produção Nacional
Revisado por pares
Frank Loray, Jorge Vitório Pereira, Frédéric Touzet,
Abstract We classify the irreducible components of the space of foliations on Fano 3‐folds with rank one Picard group. As a corollary we obtain a classification of holomorphic Poisson structures on the same class of 3‐folds.
Tópico(s): Advanced Algebra and Geometry
2013 - Wiley | Mathematische Nachrichten
Produção Nacional
Revisado por pares
Giorgio Rivalenti, Maurízio Mazzucchelli, M. Molesini, Riccardο Petrini, Vicente Antônio Vitório Girardi, Jorge Bossi, N. Campal,
Tópico(s): High-pressure geophysics and materials
1995 - Springer Science+Business Media | Mineralogy and Petrology
Produção Nacional
Revisado por pares
We prove the following theorem for Holomorphic Foliations in compact complex kaehler manifolds: if there is a compact leaf with finite holonomy, then every leaf is compact with finite holonomy. As corollary we reobtain stability theorems for compact foliations in Kaehler manifolds of Edwards-Millett-Sullivan and Hollman.
Tópico(s): Holomorphic and Operator Theory
2001 - Birkhäuser | Qualitative Theory of Dynamical Systems
Produção Nacional
Revisado por pares
We investigate the interplay between invariant varieties of vector fields and the inflection locus of linear systems with respect to the vector field. Among the consequences of such investigation we obtain a computational criterion for the existence of rational first integrals of a given degree, bounds for the number of first integrals on families of vector fields, and a generalization of Darboux's criteria. We also provide a new proof of Gomez--Mont's result on foliations with all leaves algebraic.
Tópico(s): Polynomial and algebraic computation
2001 - Association of the Annals of the Fourier Institute | Annales de l’institut Fourier
Produção Nacional
Revisado por pares
Frank Loray, Jorge Vitório Pereira, Frédéric Touzet,
The main purpose of this paper is to provide a structure theorem for codimension-one singular transversely projective foliations on projective manifolds. To reach our goal, we firstly extend Corlette-Simpson's classification of rank-two representations of fundamental groups of quasi-projective manifolds by dropping the hypothesis of quasi-unipotency at infinity. Secondly we establish a similar classification for rank-two flat meromorphic connections. In particular, we prove that a rank-two flat ...
Tópico(s): Geometric Analysis and Curvature Flows
2016 - | Journal de l’École polytechnique — Mathématiques
Produção Nacional
Revisado por pares
Benoît Claudon, Frank Loray, Jorge Vitório Pereira, Frédéric Touzet,
come from teaching and research institutions in France or abroad, or from public or private research centers.L'archive ouverte pluridisciplinaire
Tópico(s): Advanced Algebra and Geometry
2018 - Société Mathématique de France | Annales Scientifiques de l École Normale Supérieure
Produção Nacional
Revisado por pares
Frank Loray, Jorge Vitório Pereira, Frédéric Touzet,
Tópico(s): Geometric Analysis and Curvature Flows
2018 - Springer Science+Business Media | Inventiones mathematicae
Produção Nacional
Revisado por pares
Jorge Vitório Gomes das NEVES, Marília Viana BORGES, Daniel De Melo Silva, Cristina Xavier dos Santos Leite, Mariana Romana Correia Santos, Neuma Gonçalves Barbosa de Lima, Suzana Caetano da Silva Lannes, Marcondes Viana da Silva,
This study aimed to evaluate the efficiency of aqueous extraction to obtain bioactive phytochemicals from grains and residual husk of organic Arabic coffee, as well as to develop a beverage with high antioxidant capacity and assess its sensorial acceptability. Aqueous extracts were obtained from dried and crushed coffee beans and husk. Various extraction methods were used to select the one capable of extracting the most amount of total phenolic constituents. The decoction without mechanical agitation ...
Tópico(s): Biochemical Analysis and Sensing Techniques
2019 - Sociedade Brasileira de Ciência e Tecnologia de Alimentos | Food Science and Technology
Produção Nacional
Revisado por pares
Renan Lima, Jorge Vitório Pereira,
The degeneracy locus of a generically symplectic Poisson structure on a Fano manifold is always a singular hypersurface. We prove that there exists just one family of generically symplectic Poisson structures in Fano manifold with cyclic Picard group having a reduced simple normal crossing degeneracy locus.
Tópico(s): Advanced Algebra and Geometry
2014 - Wiley | Bulletin of the London Mathematical Society
Produção Nacional
Revisado por pares
Charles Favre, Jorge Vitório Pereira,
We prove that under mild hypothesis rational maps on a surface preserving webs are Lattès-like. We classify endomorphisms of $$\mathbb {P}^2$$ preserving webs, extending former results of Dabija-Jonsson.
Tópico(s): Algebraic Geometry and Number Theory
2015 - Springer Science+Business Media | Rendiconti del Circolo Matematico di Palermo Series 2
Produção Nacional
Revisado por pares
Thiago Fassarella, Jorge Vitório Pereira,
We investigate the degree of the polar transformations associated to a certain class of multi-valued homogeneous functions. In particular we prove that the degree of the preimage of generic linear spaces by a polar transformation associated to a homogeneous polynomial F is determined by the zero locus of F. For zero dimensional-dimensional linear spaces this was conjectured by Dolgachev and proved by Dimca–Papadima using topological arguments. Our methods are algebro-geometric and rely on the study ...
Tópico(s): Nonlinear Waves and Solitons
2007 - Birkhäuser | Selecta Mathematica
Produção Nacional
Revisado por pares
to {1, 2, 3, 4, 5, 6, 8, 10, 12}.We also construct an explicit projective model for Brunella's very special foliation.
Tópico(s): Geometric Analysis and Curvature Flows
2005 - Autonomous University of Barcelona | Publicacions Matemàtiques
Produção Nacional
Revisado por pares
Raphael Constant da Costa, Ruben Lizarbe, Jorge Vitório Pereira,
We establish a structure theorem for degree three codimension one foliations on projective spaces of dimension n≥3, extending a result by Loray, Pereira, and Touzet for degree three foliations on P3. We show that the space of codimension one foliations of degree three on Pn, n≥3, has exactly 18 distinct irreducible components parameterizing foliations without rational first integrals, and at least 6 distinct irreducible components parameterizing foliations with rational first integrals.
Tópico(s): Geometric Analysis and Curvature Flows
2021 - Elsevier BV | Bulletin des Sciences Mathématiques
Produção Nacional
Revisado por pares
Wilson Teixeira, Manoel S. D’Agrella-Filho, Mike A. Hamilton, Richard E. Ernst, Vicente Antônio Vitório Girardi, Maurízio Mazzucchelli, Jorge Silva Bettencourt,
The Tandilia Terrane (southernmost fringe of the Rio de la Plata Craton) is an igneous and metamorphic complex produced by an accretionary orogeny (2.25–2.02 Ga). Calc-alkaline acidic dykes with E–W strike and a major shear zone with similar orientation are related with the late orogeny stage, as supported by field relations. In a previous study the acid dykes gave 40Ar–39Ar ages of 2007 ± 24 Ma to 2020 ± 24 Ma. A N and NW trending tholeiitic dyke swarm (Tandil swarm) is also present in the Tandilia Terrane. ...
Tópico(s): High-pressure geophysics and materials
2012 - Elsevier BV | Lithos