共查询到20条相似文献,搜索用时 93 毫秒
1.
Luca Chiantini 《Ricerche di matematica》2006,55(1):93-104
Abstract The paper is concerned with some properties of linear series on smooth plane curves; in fact, we study mainly the case of
cubic curves. The main result describes the growth of the dimension of non complete linear series, generalizing to cubics
a well known result of Gieseker, about linear series on the projective lines.
Keywords: Curves, Linear series
Mathematics Subject Classification (2000): 14Q05 相似文献
2.
Tan Xiao-Jiang 《manuscripta mathematica》1992,75(1):365-373
In this paper, we give several existence theorems of rank two special stable vector bundles on smooth complex projective curves
of genusg≥2. 相似文献
3.
Marcus Zibrowius 《Mathematische Zeitschrift》2014,278(1-2):191-227
4.
Carolina Araujo 《Geometriae Dedicata》2009,139(1):289-297
In this paper we characterize smooth complex projective varieties that admit a quadric bundle structure on some dense open
subset in terms of the geometry of certain families of rational curves.
相似文献
5.
E. Ballico 《Rendiconti del Circolo Matematico di Palermo》2002,51(1):127-142
Here we study the canonical model of a reducible trigonal Gorenstein curve X. We prove that the canonical model is arithmetically
Cohen — Macaulay and lies in a minimal degree Hirzebruch surface, generalizing the classical theory of Maroni on smooth trigonal
curves. 相似文献
6.
Joseph W. Cutrone Nicholas A. Marshburn 《Central European Journal of Mathematics》2013,11(9):1552-1576
In this paper, examples of type II Sarkisov links between smooth complex projective Fano threefolds with Picard number one are provided. To show examples of these links, we study smooth weak Fano threefolds X with Picard number two and with a divisorial extremal ray. We assume that the pluri-anticanonical morphism of X contracts only a finite number of curves. The numerical classification of these particular smooth weak Fano threefolds is completed and the geometric existence of some numerical cases is proven. 相似文献
7.
Zane Kun Li 《Journal of Pure and Applied Algebra》2010,214(11):2078-2086
The intersection curve between two surfaces in three-dimensional real projective space RP3 is important in the study of computer graphics and solid modelling. However, much of the past work has been directed towards the intersection of two quadric surfaces. In this paper we study the intersection curve between a quadric and a cubic surface and its projection onto the plane at infinity. Formulas for the plane and space curves are given for the intersection of a quadric and a cubic surface. A family of cubic surfaces that give the same space curve when we intersect them with a quadric surface is found. By generalizing the methods in Wang et al. (2002) [6] that are used to parametrize the space curve between two quadric surfaces, we give a parametrization for the intersection curve between a quadric and a cubic surface when the intersection has a singularity of order 3. 相似文献
8.
We will prove two results about the topology of complex projective surfaces. The first result says that if the Shafarevich Conjecture has an affirmative answer in dimension two then the second homotopy group of a smooth projective surface is a torsion-free abelian group. The second result is that for any 2-dimensional function field K/C there is a normal projective simply-connected surface with function field K. 相似文献
9.
Yan XU & Min RU Department of Mathematics Nanjing Normal University Nanjing China Department of Mathematics University of Houston Houston TX USA 《中国科学A辑(英文版)》2007,50(5):683-688
In this paper, we prove a uniqueness theorem for algebraic curves from a compact Riemann surface into complex projective spaces. 相似文献
10.
Thomas Eckl 《manuscripta mathematica》2016,150(3-4):337-356
We add further notions to Lehmann’s list of numerical analogues to the Kodaira dimension of pseudo-effective divisors on smooth complex projective varieties, and show new relations between them. Then we use these notions and relations to fill in a gap in Lehmann’s arguments, thus proving that most of these notions are equal. Finally, we show that the Abundance Conjecture, as formulated in the context of the Minimal Model Program, and the Generalized Abundance Conjecture using these numerical analogues to the Kodaira dimension, are equivalent for non-uniruled complex projective varieties. 相似文献
11.
In this paper, we define the virtual moduli cycle of moduli spaces with perfect tangent-obstruction theory. The two interesting moduli spaces of this type are moduli spaces of vector bundles over surfaces and moduli spaces of stable morphisms from curves to projective varieties. As an application, we define the Gromov-Witten invariants of smooth projective varieties and prove all its basic properties.
12.
Using symplectic topology and the Radon transform, we prove that smooth 4-dimensional projective planes are diffeomorphic
to
. We define the notion of a plane curve in a smooth projective plane, show that plane curves in high dimensional regular planes
are lines, prove that homeomorphisms preserving plane curves are smooth collineations, and prove a variety of results analogous
to the theory of classical projective planes.
*Thanks to Robert Bryant and John Franks. 相似文献
13.
In this article, we show that the space of nodal rational curves, which is so called a Severi variety (of rational curves), on any non-singular projective surface is always
equipped with a natural Einstein–Weyl structure, if the space is 3-dimensional. This is a generalization of the Einstein–Weyl
structure on the space of smooth rational curves on a complex surface, given by Hitchin. As geometric objects naturally associated to Einstein–Weyl structure,
we investigate null surfaces and geodesics on the Severi varieties. Also, we see that if the projective surface has an appropriate
real structure, then the real locus of the Severi variety becomes a positive definite Einstein–Weyl manifold. Moreover, we
construct various explicit examples of rational surfaces having 3-dimensional Severi varieties of rational curves. 相似文献
14.
15.
KEUM JongHae 《中国科学 数学(英文版)》2011,(8)
Given any (2,4)-elliptic surface with nine smooth rational curves,eight (2)-curves and one (3)-curve,forming a Dynkin diagram of type [2,2][2,2][2,2][2,2,3],we show that a fake projective plane can be constructed from it by taking a degree 3 cover and then a degree 7 cover.We also determine the types of singular fibres of such a (2,4)-elliptic surface. 相似文献
16.
A sphere of dimension 4n+3 admits three Sasakian structures and it is natural to ask if a submanifold can be an integral submanifold for more than one of the contact structures. In the 7-sphere it is possible to have curves which are Legendre curves for all three contact structures and there are 2 and 3-dimensional submanifolds which are integral submanifolds of two of the contact structures. One of the results here is that if a 3-dimensional submanifold is an integral submanifold of one of the Sasakian structures and invariant with respect to another, it is an integral submanifold of the remaining structure and is a principal circle bundle over a holmophic Legendre curve in complex projective 3-space. 相似文献
17.
18.
Thomas Bauer 《Proceedings of the American Mathematical Society》1997,125(9):2537-2541
In this note we prove the existence of smooth Kummer surfaces in projective three-space containing sixteen mutually disjoint smooth rational curves of any given degree.
19.
Michael Temkin 《Israel Journal of Mathematics》2011,185(1):1-42
In this paper we study relative Riemann-Zariski spaces associated to a morphism of schemes and generalizing the classical
Riemann-Zariski space of a field. We prove that similarly to the classical RZ spaces, the relative ones can be described either
as projective limits of schemes in the category of locally ringed spaces or as certain spaces of valuations. We apply these
spaces to prove the following two new results: a strong version of stable modification theorem for relative curves; a decomposition
theorem which asserts that any separated morphism between quasi-compact and quasiseparated schemes factors as a composition
of an affine morphism and a proper morphism. In particular, we obtain a new proof of Nagata’s compactification theorem. 相似文献
20.
Using vertex algebra techniques, we determine a set of generators for the cohomology ring of the Hilbert schemes of points
on an arbitrary smooth projective surface over the field of complex numbers.
Received: 28 November 2000 / Published online: 23 May 2002 相似文献