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We address the problem of classification of contact Fano manifolds. It is conjectured that every such manifold is necessarily homogeneous. We prove that the Killing form, the Lie algebra grading and parts of the Lie bracket can be read from…

Algebraic Geometry · Mathematics 2021-02-16 Jarosław Buczyński

In this paper we study holomorphic Legendrian curves in the standard holomorphic contact structure on $\mathbb{C}^{2n+1}$ for any $n\in\mathbb{N}$. We provide several approximation and desingularization results which enable us to prove…

Complex Variables · Mathematics 2019-02-20 Antonio Alarcon , Franc Forstneric , Francisco J. Lopez

In this paper we study smooth complex projective polarized varieties (X,H) of dimension n \ge 2 which admit a dominating family V of rational curves of H-degree 3, such that two general points of X may be joined by a curve parametrized by…

Algebraic Geometry · Mathematics 2010-03-26 Gianluca Occhetta , Valentina Paterno

We study the deformation theory of rational curves on primitive symplectic varieties and show that if the rational curves cover a divisor, then, as in the smooth case, they deform along their Hodge locus in the universal locally trivial…

Algebraic Geometry · Mathematics 2021-03-31 Christian Lehn , Giovanni Mongardi , Gianluca Pacienza

This paper deals with rational curves and birational contractions on irreducible holomorphically symplectic manifold. We survey some recent results about minimal rational curves, their deformations, extremal rays associated with these…

Algebraic Geometry · Mathematics 2020-11-18 Ekaterina Amerik , Misha Verbitsky

We study various generalisations of rationally connected varieties, allowing the connecting curves to be of higher genus. The main focus will be on free curves $f:C\to X$ with large unobstructed deformation space as originally defined by…

Algebraic Geometry · Mathematics 2016-03-09 Frank Gounelas

The minimal surface equation $Q$ in the second order contact bundle of $R^3$, modulo translations, is provided with a complex structure and a canonical vector-valued holomorphic differential form $Omega$ on $Q\0$. The minimal surfaces $M$…

Differential Geometry · Mathematics 2007-05-23 J. J. Duistermaat

A complex projective manifold is rationally connected, resp. rationally simply connected, if finite subsets are connected by a rational curve, resp. the spaces parameterizing these connecting rational curves are themselves rationally…

Algebraic Geometry · Mathematics 2017-06-20 Jason Starr , Chenyang Xu

This is a survey of recent works on the germ-equivalence problem of minimal rational curves on uniruled projective manifolds. Our main interest is when the associated varieties of minimal rational tangents form an isotrivial family of…

Algebraic Geometry · Mathematics 2026-05-26 Jun-Muk Hwang

In this paper, we study normal complex contact metric manifolds and we get some general results on them. Moreover, we obtained the general expression of the curvature tensor field for arbitrary vector fields. Furthermore, we show that the…

Differential Geometry · Mathematics 2015-10-21 Aysel Turgut Vanli , Inan Unal

Let $X$ be a smooth complex projective variety and let $H \in \pic(X)$ be an ample line bundle. Assume that $X$ is covered by rational curves with degree one with respect to $H$ and with anticanonical degree greater than or equal to $(\dim…

Algebraic Geometry · Mathematics 2019-08-15 Carla Novelli , Gianluca Occhetta

A cone structure on a complex manifold $M$ is a closed submanifold $\mathcal C \subset \mathbb P TM$ of the projectivized tangent bundle which is submersive over $M$. A conic connection on $\mathcal C$ specifies a distinguished family of…

Differential Geometry · Mathematics 2020-10-30 Jun-Muk Hwang , Katharina Neusser

We study a cone structure ${\mathcal C} \subset {\mathbb P} D$ on a holomorphic contact manifold $(M, D \subset T_M)$ such that each fiber ${\mathcal C}_x \subset {\mathbb P} D_x$ is isomorphic to a Legendrian submanifold of fixed…

Differential Geometry · Mathematics 2020-10-22 Jun-Muk Hwang

We formulate the equivalence problem, in the sense of E. Cartan, for families of minimal rational curves on uniruled projective manifolds. An important invariant of this equivalence problem is the variety of minimal rational tangents. We…

Algebraic Geometry · Mathematics 2009-08-17 Jun-Muk Hwang

In this article I propose a new method for reducing a co-oriented contact manifold M equipped with an action of a Lie group G by contact transformations. With a certain regularity and integrality assumption the contact quotient $M_\mu$ at…

Symplectic Geometry · Mathematics 2007-05-23 Christopher Willett

Using convex integration we give a constructive proof of the well-known fact that every continuous curve in a contact $3$-manifold can be approximated by a Legendrian curve.

Differential Geometry · Mathematics 2017-03-29 Norbert Hungerbühler , Thomas Mettler , Micha Wasem

We study rational curves on general Fano hypersurfaces in projective space, mostly by degenerating the hypersurface along with its ambient projective space to reducible varieties. We prove results on existence of low-degree rational curves…

Algebraic Geometry · Mathematics 2020-03-11 Ziv Ran

Codimension 2 contact submanifolds are the natural generalization of transverse knots to contact manifolds of arbitrary dimension. In this paper, we construct new invariants of codimension 2 contact submanifolds. Our main invariant can be…

Symplectic Geometry · Mathematics 2024-03-06 Laurent Côté , François-Simon Fauteux-Chapleau

A variety $X$ is covered by lines if there exist a finite number of lines contained in $X$ passing through each general point. I prove two theorems. Theorem 1:Let $X^n\subset P^M$ be a variety covered by lines. Then there are at most $n!$…

Algebraic Geometry · Mathematics 2007-05-23 J. M. Landsberg

We study minimal surfaces in generic sub-Riemannian manifolds with sub-Riemannian structures of co-rank one. These surfaces can be defined as the critical points of the so-called {\it horizontal} area functional associated to the canonical…

Analysis of PDEs · Mathematics 2007-09-20 Nataliya Shcherbakova