共查询到20条相似文献,搜索用时 15 毫秒
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Gonzalo Comas 《Journal of Pure and Applied Algebra》2011,215(8):1822-1834
We define the C-rank associated to a projective curve and describe the strata of points having constant rank. 相似文献
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Let C be an irreducible plane curve. A point P in the projective plane is said to be Galois with respect to C if the function field extension induced by the projection from P is Galois. We denote by δ′(C) the number of Galois points contained in P2?C. In this article we will present two results with respect to determination of δ′(C) in characteristic two. First we determine δ′(C) for smooth plane curves of degree a power of two. In particular, we give a new characterization of the Klein quartic in terms of δ′(C). Second we determine δ′(C) for a generalization of the Klein quartic, which is related to an example of Artin–Schreier curves whose automorphism group exceeds the Hurwitz bound. This curve has many Galois points. 相似文献
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It is well known that a finite graph can be viewed, in many respects, as a discrete analogue of a Riemann surface. In this paper, we pursue this analogy further in the context of linear equivalence of divisors. In particular, we formulate and prove a graph-theoretic analogue of the classical Riemann-Roch theorem. We also prove several results, analogous to classical facts about Riemann surfaces, concerning the Abel-Jacobi map from a graph to its Jacobian. As an application of our results, we characterize the existence or non-existence of a winning strategy for a certain chip-firing game played on the vertices of a graph. 相似文献
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Yves Laszlo 《Advances in Mathematics》2004,185(2):246-269
Let X be a smooth projective curve of genus g?2 defined over an algebraically closed field k of characteristic p>0. Let MX(r) be the moduli space of semi-stable vector bundles with fixed trivial determinant. The relative Frobenius map induces by pull-back a rational map . We determine the equations of V in the following two cases (1) (g,r,p)=(2,2,2) and X nonordinary with Hasse-Witt invariant equal to 1 (see math.AG/0005044 for the case X ordinary), and (2) (g,r,p)=(2,2,3). We also show the existence of base points of V, i.e., semi-stable bundles E such that F∗E is not semi-stable, for any triple (g,r,p). 相似文献
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Indranil Biswas 《Bulletin des Sciences Mathématiques》2005,129(6):539-543
Let X be a smooth projective curve defined over an algebraically closed field of positive characteristic. We give a necessary and sufficient condition for a vector bundle over X to be ample. This generalizes a criterion given by Lange in [Math. Ann. 238 (1978) 193-202] for a rank two vector bundle over X to be ample. 相似文献
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Let G be a complex semisimple group and χ a character of a parabolic subgroup P⊂G such that the associated line bundle on G/P is ample. For a general stable G-bundle EG over a compact Riemann surface of genus at least two, the line bundle over EG/P defined by χ has the property that the restriction of to any closed subvariety of EG/P of smaller dimension is ample, although is not ample. 相似文献
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Charles H. Walter 《Mathematische Annalen》1995,301(1):699-715
Supported in part by NSA research grant MDA904-92-H-3009 相似文献
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Marco Franciosi 《Advances in Mathematics》2004,186(2):317-333
Let C be a numerically connected curve lying on a smooth algebraic surface. We show that if is an ample invertible sheaf satisfying some technical numerical hypotheses then is normally generated. As a corollary we show that the sheaf ωC⊗2 on a numerically connected curve C of arithmetic genus pa?3 is normally generated if ωC is ample and does not exist a subcurve B⊂C such that pa(B)=1=B(C−B). 相似文献
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Claudio Fontanari 《Archiv der Mathematik》2007,89(6):530-535
We prove that the orbifold desingularization of the moduli space of stable maps of genus g = 1 recently constructed by Vakil and Zinger has vanishing rational cohomology groups in odd degree k < 11.
Received: 29 January 2007 相似文献
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E. Ballico 《Geometriae Dedicata》1994,53(3):327-332
Here we study the connectedness of the scheme of multisecant linear spaces to a curveC P
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3 with non-special hyperplane section. 相似文献
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We find that every reduced and irreducible curve C on a smooth cubic surface is k-Buchsbaum, with k equal to the diameter of the Rao module M(C). Moreover we determine the diameters of the submodules generated by all the elements with the same degree in a minimal set of generators of M(C). 相似文献
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We study the structure of the function field K of the quintic Fermat curve F(5) in the following way: Let K m be a g-maximal rational subfield of K. Then the field extension K/K m is obtained by the projection from F(5) to a line with a center p, ∈ F(5). By using this fact, we consider the field extension K/K m from several point of view. 相似文献
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Juan Elias 《Journal of Pure and Applied Algebra》2008,212(8):1853-1877
The main purpose of this paper is to prove the existence of the moduli space parameterizing the embedded curve singularities of with an admissible Hilbert polynomial p and to study its basic properties. 相似文献
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C. Douglas Haessig 《Journal of Number Theory》2009,129(5):1161-1177
Given a projective variety X defined over a finite field, the zeta function of divisors attempts to count all irreducible, codimension one subvarieties of X, each measured by their projective degree. When the dimension of X is greater than one, this is a purely p-adic function, convergent on the open unit disk. Four conjectures are expected to hold, the first of which is p-adic meromorphic continuation to all of Cp. When the divisor class group (divisors modulo linear equivalence) of X has rank one, then all four conjectures are known to be true. In this paper, we discuss the higher rank case. In particular, we prove a p-adic meromorphic continuation theorem which applies to a large class of varieties. Examples of such varieties are projective nonsingular surfaces defined over a finite field (whose effective monoid is finitely generated) and all projective toric varieties (smooth or singular). 相似文献