共查询到20条相似文献,搜索用时 15 毫秒
1.
Robin Hartshorne 《Annali dell'Universita di Ferrara》1994,40(1):207-223
LetC be a curve contained in ℙ
k
3
(k of any characteristic), which is locally Cohen-Macaulay, not contained in a plane and of degreed. We prove thatp
a
(C)≤≤((d−2)(d−3))/2. Moreover we show existence of curves with anyd, p
a
satisfying this inequality and we characterize those curves for which equality holds.
Sunto Si dimostra che seC⊃ℙ k 3 (k di caratteristica qualunque) é una curva, non piana, localmente Cohen-Macaulay, di gradod, allorap a (C)≤((d−2)(d−3))/2. Si mostra che questa limitazione è ottimale, e si classificano le curve di genere aritmetico massimale.相似文献
2.
Naoki Murabayashi 《manuscripta mathematica》1994,84(1):125-133
We consider the moduli spaceS
n
of curvesC of genus 2 with the property:C has a “maximal” mapf of degreen to an elliptic curveE. Here, the term “maximal” means that the mapf∶C→E doesn't factor over an unramified cover ofE. By Torelli mapS
n
is viewed as a subset of the moduli spaceA
2 of principally polarized abelian surfaces. On the other hand the Humbert surfaceH
Δ of invariant Δ is defined as a subvariety ofA
2(C), the set of C-valued points ofA
2. The purpose of this paper is to releaseS
n
withH
Δ. 相似文献
3.
Hao Sun 《Czechoslovak Mathematical Journal》2018,68(4):1079-1089
We give an estimation for the arithmetic genus of an integral space curve which is not contained in a surface of degree k?1. Our main technique is the Bogomolov-Gieseker type inequality for ?3 proved by Macrì. 相似文献
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5.
Charles H. Walter 《代数通讯》2013,41(13):5167-5174
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Using the Mori theory for threefolds, we prove that the moduli space of pairs of smooth curves of genus four and theta characteristics without global sections is a rational variety. 相似文献
9.
We explicitly describe complete, one-dimensional subvarieties of the moduli space of smooth complex curves of genus 3.Supported by the Netherlands Organization for Scientific Research (N.W.O.). 相似文献
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11.
Alberto Dolcetti 《Annali dell'Universita di Ferrara》1989,35(1):17-23
Riassunto Se il genere è alto, le curve di rango massimo sono proiettivamente normali. La nozione di ?genere alto? è precisata fornendo
un limite explicito, dipendente solo dal grado.
Dal 14 giugno 1990: Dip. di Matematica ?U. Dini?, viale Morgagni 67/A, 50134 Firenze. 相似文献
Summary Maximal rank space curves of high genus are projectively normal. We precise the meaning of ?high genus?, by giving an explicit bound, depending only on the degree.
Dal 14 giugno 1990: Dip. di Matematica ?U. Dini?, viale Morgagni 67/A, 50134 Firenze. 相似文献
12.
Michela Artebani 《Transactions of the American Mathematical Society》2008,360(3):1581-1599
S. Kondo used periods of surfaces to prove that the moduli space of genus three curves is birational to an arithmetic quotient of a complex 6-ball. In this paper we study Heegner divisors in the ball quotient, given by arithmetically defined hyperplane sections of the ball. We show that the corresponding loci of genus three curves are given by hyperelliptic curves, singular plane quartics and plane quartics admitting certain rational ``splitting curves'.
13.
We give a new method for generating genus 2 curves over a finite field with a given number of points on the Jacobian of the curve. We define two new invariants for genus 2 curves as values of modular functions on the Hilbert moduli space and show how to compute them. We relate them to the usual three Igusa invariants on the Siegel moduli space and give an algorithm to construct curves using these new invariants. Our approach simplifies the complex analytic method for computing genus 2 curves for cryptography and reduces the amount of computation required. 相似文献
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Özgür Ceyhan 《Selecta Mathematica, New Series》2007,13(2):203-237
The moduli space parameterizes the isomorphism classes of S-pointed stable real curves of genus zero which are invariant under relabeling by the involution σ. This moduli space is stratified according to the degeneration types of σ-invariant curves. The degeneration types of σ-invariant curves are encoded by their dual trees with additional decorations. We construct a combinatorial graph complex
generated by the fundamental classes of strata of . We show that the homology of is isomorphic to the homology of our graph complex. We also give a presentation of the fundamental group of .
相似文献
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Luisella Caire 《manuscripta mathematica》1991,71(1):361-374
We characterize plane curves Γ of genus p and degree 2p with respect to the possibility of obtaining them as projections of
space curves C′ of the same degree. When Γ is hyperelliptic, we link this characterization with the configuration of the singularities
of Γ and with the position of C′ on certain scrolls.
Supported by the M.U.R.S.T. of the Italian Government 相似文献
18.
Enrique Gonzá lez-Jimé nez Josep Gonzá lez. 《Mathematics of Computation》2003,72(241):397-418
We prove that there are exactly genus two curves defined over such that there exists a nonconstant morphism defined over and the jacobian of is -isogenous to the abelian variety attached by Shimura to a newform . We determine the corresponding newforms and present equations for all these curves.
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