共查询到20条相似文献,搜索用时 15 毫秒
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Tie Luo 《Mathematische Annalen》2000,318(4):707-730
The change of zero locus of a global holomorphic 2-form on a threefold under birational transformations is investigated. It is proved that existence of 2-forms with certain conditions on their zero loci on a threefold of nonnegative Kodaira dimension limits types of terminal singularities appearing on its minimal models. As a result of the restriction on the types of terminal singularities and Reid's Riemann-Roch formula, a universal bound N is found such that the linear system NK defines a birational map from a threefold of general type admitting those 2-forms, where K is the canonical bundle of the threefold. Received March 10, 2000 / Published online October 11, 2000 相似文献
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Paolo Salani 《manuscripta mathematica》1998,96(3):281-294
This paper is concerned with large solutions of Hessian equations , in a strictly k-convex domain , i.e. solutions such that as . We prove existence, in the viscosity sense, of this kind of solutions assuming that g satisfies some natural growth conditions. Non-existence and uniqueness results are given too.
Received: 18 November 1997 相似文献
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Paul Freitag 《Mathematische Annalen》1997,309(2):179-198
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Jin-Xing Cai 《Mathematische Zeitschrift》2002,240(3):511-519
Received: 15 October 1999; in final form: 13 June 2000 / Published online: 29 April 2002 相似文献
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Dongho Chae Oleg Y. Imanuvilov 《Calculus of Variations and Partial Differential Equations》2003,16(1):47-61
In this paper we construct a non-topological multivortex solution of a generalized version of the relativistic self-dual
Chern-Simons-Higgs system in that makes the energy functional finite. Our method of proof is an extension of the previous argument used by the authors
to prove the existence of general type of non-topological multivortex solutions of the relativistic Chern-Simons-Higgs system,
using an implicit function theorem argument with features similar to the Liapunov-Schmidt decomposition.
Received: 20 January 2001 / Accepted: 25 October 2001 / Published online: 29 April 2002
This research supported partially by BSRI-MOE, KOSEF(2000-2-10200-002-5). 相似文献
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Lucio Guerra 《manuscripta mathematica》1999,98(1):1-8
We provide a general estimate for the number of irreducible components of a Chow variety, the variety that parametrizes algebraic
cycles of given dimension and degree contained in a projective variety. The result is then applied to obtain an upper bound
for the finite number of surfaces of general type that are images of a fixed surface.
Received: 29 January 1998 / Revised version: 24 June 1998 相似文献
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Massimo Grossi Angela Pistoia Juncheng Wei 《Calculus of Variations and Partial Differential Equations》2000,11(2):143-175
We study a perturbed semilinear problem with Neumann boundary condition
where is a bounded smooth domain of , , , if or if and is the unit outward normal at the boundary of . We show that for any fixed positive integer K any “suitable” critical point of the function
generates a family of multiple interior spike solutions, whose local maximum points tend to as tends to zero.
Received March 7, 1999 / Accepted October 1, 1999 / Published online April 6, 2000 相似文献
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Xi-Nan Ma 《Mathematische Zeitschrift》2002,240(1):1-11
We study solutions of the nonlinear elliptic equation on a bounded domain in . It is shown that the set of points where the graph of the solution has negative Gauss curvature always extends to the boundary, unless it is empty.
The meethod uses an elliptic equation satisfied by an auxiliary function given by the product of the Hessian determinant and
a suitable power of the solutions. As a consequence of the result, we give a new proof for power concavity of solutions to
certain semilinear boundary value problems in convex domains.
Received: 12 January 2000; in final form: 15 March 2001 / Published online: 4 April 2002 相似文献
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Shinji Adachi Kazunaga Tanaka 《Calculus of Variations and Partial Differential Equations》2000,11(1):63-95
We consider the existence of positive solutions of the following semilinear elliptic problem in : where , , , and . Under the conditions: 1° for all , 2° as , 3° there exist and such that 4°, we show that (*) has at least four positive solutions for sufficiently small but . Received December 11, 1998 / Accepted July 16, 1999 / Published online April 6, 2000 相似文献
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Daisuke Matsushita 《Mathematische Annalen》2001,321(4):755-773
We classify singular fibres over general points of the discriminant locus of projective Lagrangian fibrations over 4-dimensional
holomorphic symplectic manifolds. The singular fibre F is the following either one: F is isomorphic to the product of an elliptic curve and a Kodaira singular fibre up to finite unramified covering or F is a normal crossing variety consisting of several copies of a minimal elliptic ruled surface of which the dual graph is
Dynkin diagram of type or . Moreover, we show all types of the above singular fibres actually occur.
Received: 10 March 2000 / Revised version: 29 September 2000 / Published online: 24 September 2001 相似文献
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In this work we show a singular K3 surface S of such that producing a counter-example to a conjecture of Veys.
Received: 22 October 1999 相似文献
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Y.-P. Lee 《Inventiones Mathematicae》2001,145(1):121-149
The mirror theorem is generalized to any smooth projective variety X. That is, a fundamental relation between the Gromov–Witten invariants of X and Gromov–Witten invariants of complete intersections Y in X is established.
Oblatum 21-IV-2000 & 11-I-2001?Published online: 2 April 2001 相似文献
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Stephan Endraß 《manuscripta mathematica》1999,99(3):341-358
For a double solid V→ℙ3> branched over a surface B⊂ℙ3(ℂ) with only ordinary nodes as singularities, we give a set of generators of the divisor class group in terms of contact surfaces of B with only superisolated singularities in the nodes of B. As an application we give a condition when H
* (˜V , ℤ) has no 2-torsion. All possible cases are listed if B is a quartic. Furthermore we give a new lower bound for the dimension of the code of B.
Received: 16 November 1998 相似文献
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Sijong Kwak 《Mathematische Annalen》2001,320(4):649-664
For a projective variety X of codimension 2 in defined over the complex number field , it is traditionally said that X has no apparent -ple points if the -secant lines of X do not fill up the ambient projective space , equivalently, the locus of -ple points of a generic projection of X to ${\Bbb P}^{n+1}$ is empty. We show that a smooth threefold in has no apparent triple points if and only if it is contained in a quadric hypersurface. We also obtain an enumerative formula
counting the quadrisecant lines of X passing through a general point of and give necessary cohomological conditions for smooth threefolds in without apparent quadruple points. This work is intended to generalize the work of F. Severi [fSe] and A. Aure [Au], where
it was shown that a smooth surface in has no triple points if and only if it is either a quintic elliptic scroll or contained in a hyperquadric. Furthermore we
give open questions along these lines.
Received: 24 January 2000 / Published online: 18 June 2001 相似文献