共查询到20条相似文献,搜索用时 15 毫秒
1.
Takashi Kishimoto 《Journal of Pure and Applied Algebra》2007,208(1):189-204
Let X?(T,D) be a compactification of an affine 3-fold X into a smooth projective 3-fold T such that the (reduced) boundary divisor D is SNC. In this paper, as an affine counterpart to the work due to S. Mori (cf. [S. Mori, Threefolds whose canonical bundles are not numerically effective, Ann. of Math. 116 (1982) 133-176]), we shall classify (K+D)-negative extremal rays on T. In particular, if such an extremal ray R=R+[C] intersects K non-negatively, we shall describe the log flips and divisorial contractions appearing explicitly. 相似文献
2.
3.
G. Berhuy 《Advances in Mathematics》2005,198(1):128-171
We define and study a numerical invariant of an algebraic group action which we call the canonical dimension. We then apply the resulting theory to the problem of computing the minimal number of parameters required to define a generic hypersurface of degree d in Pn-1. 相似文献
4.
Gianluca Occhetta 《manuscripta mathematica》2001,104(1):111-121
In this paper we classify pairs (X,ℰ) with ℰ ample vector bundle of rank r on a smooth variety X of dimension n= 2r−1 such that K
X
+ det ℰ=?
x
.
Received: 7 April 2000 相似文献
5.
Let X be a complete toric variety and Y a smooth projective variety with . We prove that, if is a surjective morphism then .
Received: 15 May 2001; in final form: 22 October 2001/ Published online: 4 April 2002 相似文献
6.
Giacomo Lenzi 《Mathematical Logic Quarterly》2011,57(5):474-480
We introduce a quite natural Frege‐style set theory, which we call Strong‐Frege‐2 $(\mathsf {SF}_2)$, a sort of simplification of the theory considered in 13 (under the name Strong‐Frege‐3) and 1 (under the name F2). We give a model of a weaker variant of $\mathsf {SF}_2$, called $\mathsf {SF}_2\mathsf {AC}$, where atoms and coatoms are allowed. To construct the model we use an enumeration “almost without repetitions” of the Π11 sets of natural numbers; such an enumeration can be obtained via a classical priority argument much in the style of 5 and 15 . © 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim 相似文献
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9.
Amaël Broustet 《Mathematische Annalen》2009,343(4):727-755
We show how to use effective non-vanishing to prove that Seshadri constants of some ample divisors are bigger than 1 on smooth
threefolds whose anticanonical bundle is nef or on Fano varieties of small coindice. We prove the effective non-vanishing
conjecture of Ionescu–Kawamata in dimension 3 in the case of line bundles of “high” volume. 相似文献
10.
Fumiharu Kato 《manuscripta mathematica》2001,104(4):451-458
We discuss Mumford curves in the pencil on a Del Pezzo quintic surface constructed by Edge [Ed1]. The abstract group structures
of the normalizer of the corresponding Schottky groups are described, which give us some knowledges on Mumford loci in moduli
space of curves.
Received: 5 July 2000 / Accepted: 23 October 2000 相似文献
11.
Kit Ian Kou Ming‐Sheng Liu Shu‐Zhen Tao 《Mathematical Methods in the Applied Sciences》2016,39(18):5607-5618
The present paper first introduces the notion of quaternion infinite series of positive term and establishes its several tests. Next, we give the definitions of the positive‐definite quaternion sequence and the positive semi‐definite quaternion function, and we extend the classical Herglotz's theorem to the quaternion linear canonical transform setting. Then we investigate the properties of the two‐sided quaternion linear canonical transform, such as time shift characteristics and differential characteristics. Finally, we derive its several basic properties of the quaternion linear canonical transform of a probability measure, in particular, and establish the Bochner–Minlos theorem. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
12.
We show the nonvanishing of H
0(X,−K
X
) for any a Fano 3-fold X for which −K
X
is a multiple of another Weil divisor in Cl(X). The main case we study is Fano 3-folds with Fano index 2: that is, 3-folds X with rank Pic(X)=1, -factorial terminal singularities and −K
X
= 2A for an ample Weil divisor A. We give a first classification of all possible Hilbert series of such polarised varieties (X,A) and deduce both the nonvanishing of H
0(X,−K
X
) and the sharp bound (−K
X
)3≥ 8/165. We find the families that can be realised in codimension up to 4. 相似文献
13.
Aaron D. Magid 《Mathematische Annalen》2009,344(4):877-889
We provide an infinite family of pared manifolds with the property that the relative deformation spaces of hyperbolic structures
on these manifolds are not locally connected. This is a natural extension of the recent result of Bromberg that shows the
space of Kleinian punctured torus groups is not locally connected.
The author was partially supported by the NSF RTG grant #0602191. 相似文献
14.
Thomas Ludsteck 《Archiv der Mathematik》2009,92(6):585-592
We are investigating homogeneous p-adic vector bundles on abelian varieties that are analytic tori. We show that for each homogeneous vector bundle on such
a variety there exists an integer N > 0, such that the pullback of this vector bundle via the N-multiplication is attached to an integral representation of the topological fundamental group.
Received: 8 July 2008 相似文献
15.
Paolo Piccione Daniel V. Tausk 《Calculus of Variations and Partial Differential Equations》2002,15(4):529-551
We generalize the Morse index theorem of [12,15] and we apply the new result to obtain lower estimates on the number of geodesics
joining two fixed non conjugate points in certain classes of semi-Riemannian manifolds. More specifically, we consider semi-Riemannian
manifolds admitting a smooth distribution spanned by commuting Killing vector fields and containing a maximal negative distribution
for . In particular we obtain Morse relations for stationary semi-Riemannian manifolds (see [7]) and for the G?del-type manifolds (see [3]).
Received: 4 April 2001 / Accepted: 27 September 2001 / Published online: 23 May 2002
The authors are partially sponsored by CNPq (Brazil) Proc. N. 301410/95 and N. 300254/01-6. Parts of this work were done during
the visit of the two authors to the IMPA, Instituto de Matemática Pura e Aplicada, Rio de Janeiro, Brazil, in January and
February 2001. The authors wish to express their gratitude to all Faculty and Staff of the IMPA for their kind hospitality. 相似文献
16.
Anatoly Libgober 《manuscripta mathematica》2002,107(2):251-269
Multivariable Alexander invariants of algebraic links calculated in terms of algebro-geometric invariants (polytopes and
ideals of quasiadjunction). The relations with log-canonical divisors, the multiplier ideals and a semicontinuity property
of polytopes of quasiadjunction are discussed.
Received: 8 February 2001 / Revised version: 1 December 2001 相似文献
17.
Boris Pasquier 《Mathematische Annalen》2009,344(4):963-987
We classify all smooth projective horospherical varieties with Picard number 1. We prove that the automorphism group of any
such variety X acts with at most two orbits and that this group still acts with only two orbits on X blown up at the closed orbit. We characterize all smooth projective two-orbit varieties with Picard number 1 that satisfy
this latter property. 相似文献
18.
Otmar Venjakob 《Journal of the European Mathematical Society》2002,4(3):271-311
This paper is motivated by the question whether there is a nice structure theory of finitely generated modules over the Iwasawa
algebra, i.e. the completed group algebra, Λ of a p-adic analytic group G. For G without any p-torsion element we prove that Λ is an Auslander regular ring. This result enables us to give a good definition of the notion
of a pseudo-nullΛ-module. This is classical when G=ℤ
k
p
for some integer k≥1, but was previously unknown in the non-commutative case. Then the category of Λ-modules up to pseudo-isomorphisms is studied
and we obtain a weak structure theorem for the ℤ
p
-torsion part of a finitely generated Λ-module. We also prove a local duality theorem and a version of Auslander-Buchsbaum
equality. The arithmetic applications to the Iwasawa theory of abelian varieties are published elsewhere.
Received May 12, 2001 / final version received July 5, 2001?Published online September 3, 2001 相似文献
19.
Sara Arias‐de‐Reyna Wojciech Gajda Sebastian Petersen 《Mathematische Nachrichten》2013,286(13):1269-1286
In this paper we prove the Geyer‐Jarden conjecture on the torsion part of the Mordell‐Weil group for a large class of abelian varieties defined over finitely generated fields of arbitrary characteristic. The class consists of all abelian varieties with big monodromy, i.e., such that the image of Galois representation on ?‐torsion points, for almost all primes ?, contains the full symplectic group. 相似文献
20.
Lei Zhu 《manuscripta mathematica》2009,129(1):99-126
For a canonical threefold of general type, we know that the pluri–canonical map is stably birational for a sufficiently large n. This paper aims to find the lower bound of n for such kind of threefolds with χ = 1. To prove our main result, we will estimate the lower bound of plurigenus.
L. Zhu is supported by Fudan Graduate Students’ Innovation Projects (EYH5928004). 相似文献