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In this paper, we classify codimension one foliations on adjoint varieties with most positive anti-canonical class. We show that on adjoint varieties with Picard number one, these foliations are always induced by a pencil of hyperplane…

Algebraic Geometry · Mathematics 2025-07-31 Crislaine Kuster

We study the existence of surfaces with constant or prescribed Gauss curvature in certain Lorentzian spacetimes. We prove in particular that every (non-elementary) 3-dimensional maximal globally hyperbolic spatially compact spacetime with…

General Relativity and Quantum Cosmology · Physics 2013-01-18 Thierry Barbot , François Béguin , Abdelghani Zeghib

Let $\mathcal F(r, d)$ denote the moduli space of algebraic foliations of codimension one and degree $d$ in complex proyective space of dimension $r$. We show that $\mathcal F(r, d)$ may be represented as a certain linear section of a…

Algebraic Geometry · Mathematics 2011-11-24 Fernando Cukierman

Using the Kodaira dimension and the fundamental group of X, we succeed in classifying algebraic surfaces which are dominable by C^2 except for certain cases in which X is an algebraic surface of Kodaira dimension zero and the case when X is…

Complex Variables · Mathematics 2016-09-07 Gregery T. Buzzard , Stephen Lu

Let $\pi:Z\rightarrow\mathbb{P}^{n-1}$ be a general minimal $n$-fold conic bundle with a hypersurface $B_Z\subset\mathbb{P}^{n-1}$ of degree $d$ as discriminant. We prove that if $d\geq 4n+1$ then $-K_Z$ is not pseudo-effective, and that if…

Algebraic Geometry · Mathematics 2023-10-06 Alex Massarenti , Massimiliano Mella

We investigate the algebraic genericity of various families of continuous functions exhibiting extreme irregularity, focusing on fractal dimensions, H\"older regularity, and fractional differentiability. Our first main result shows that for…

Functional Analysis · Mathematics 2026-02-20 Céline Esser , Saeid Maghsoudi , Daniel L. Rodríguez-Vidanes , Juan. B. Seoane-Sepúlveda

We show that every smooth cubic hypersurface X in P^{n+1}, n> 1 is algebraically elliptic in Gromov's sense. This gives the first examples of non-rational projective manifolds elliptic in Gromov's sense. We also deduce that the punctured…

Algebraic Geometry · Mathematics 2025-01-30 Shulim Kaliman , Mikhail Zaidenberg

We explore the existence of irreducible and reducible arc-sections in an irreducible hypersurface singularity germ along finite projections. In particular we provide examples of irreducible isolated hypersurface singularities for which no…

Algebraic Geometry · Mathematics 2019-04-02 Miguel Angel Marco-Buzunariz , Maria Pe Pereira

In this paper, we prove some splitting results for manifolds supporting a non-constant infinity harmonic function which has at most linear growth on one side. Manifolds with non-negative Ricci or sectional curvature are considered. In…

Differential Geometry · Mathematics 2024-10-15 Damião J. Araújo , Marco Magliaro , Luciano Mari , Leandro F. Pessoa

We consider A-hypergeometric functions associated to normal sets in the plane. We give a classification of all point configurations for which there exists a parameter vector such that the associated hypergeometric function is algebraic. In…

Classical Analysis and ODEs · Mathematics 2013-03-28 Esther Bod

We give an algorithm to decide whether an algebraic plane foliation F has a rational first integral and to compute it in the affirmative case. The algorithm runs whenever we assume the polyhedrality of the cone of curves of the surface…

Dynamical Systems · Mathematics 2007-05-23 C. Galindo , F. Monserrat

We investigate the accumulation to singular points of leaves of codimension one foliations whose normal bundle is ample, with emphasis on the nonexistence of Levi-flat hypersurfaces.

Complex Variables · Mathematics 2007-06-12 Marco Brunella

For a semialgebraic set K in R^n, let P_d(K) be the cone of polynomials in R^n of degrees at most d that are nonnegative on K. This paper studies the geometry of its boundary. When K=R^n and d is even, we show that its boundary lies on the…

Optimization and Control · Mathematics 2010-04-26 Jiawang Nie

Let $X$ be a compact K\"ahler manifold and $\alpha$ be a class in the Dolbeault cohomology class of bidegree $(1, 1)$ on $X$. When the numerical dimension of $\alpha$ is one and $\alpha$ admits at least two smooth semi-positive…

Complex Variables · Mathematics 2021-10-25 Takayuki Koike

We recast elliptic surfaces over the projective line in terms of the non-commutative tori and one-parameter families of the periodic continued fractions. The correspondence is used to study the Picard numbers, the ranks and the minimal…

Algebraic Geometry · Mathematics 2024-04-29 Igor Nikolaev

A generalization of Lozanovskii's result is proved. Let E be $k$-dimensional subspace of an $n$-dimensional Banach space with unconditional basis. Then there exist $x_1,..,x_k \subset E$ such that $B_E \p \subset \p absconv\{x_1,..,x_k\}$…

Functional Analysis · Mathematics 2016-09-06 Marius Junge

For every complete toric variety, there exists a projective toric variety which is isomorphic to it in codimension one. In this paper, we show that every smooth non-projective complete toric threefold of Picard number at most five becomes…

Algebraic Geometry · Mathematics 2025-07-15 Osamu Fujino , Hiroshi Sato

In this work we study the geometric properties of spacelike foliations by hypersurfaces on a Lorentz manifold. We find an equation that relates the foliation with the ambient manifold and apply it to investigate conditions for the leaves…

Differential Geometry · Mathematics 2023-08-29 Rosa Maria dos Santos Barreiro Chaves , Euripedes Carvalho da Silva

We study the classification of singularities of holomorphic foliations and non-integrable one-forms under the hypothesis of transversality with real hypersurfaces.

Complex Variables · Mathematics 2010-12-15 Toshikazu Ito , Bruno Scardua

Cubic surfaces in characteristic two are investigated from the point of view of prime characteristic commutative algebra. In particular, we prove that, the non-Frobenius split cubic surfaces form a linear subspace of codimension four in the…

Commutative Algebra · Mathematics 2022-05-16 Zhibek Kadyrsizova , Jennifer Kenkel , Janet Page , Jyoti Singh , Karen E. Smith , Adela Vraciu , Emily E. Witt