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K3 surfaces of finite height over finite fields 有限域上有限高的K3曲面
Q2 Mathematics Pub Date : 2007-09-13 DOI: 10.1215/KJM/1250271381
J.-D. Yu, N. Yui
Arithmetic of K3 surfaces defined over finite fields is investigated. In particular, we show that any K3 surface of finite height over a finite field k of characteristic p > 3 has a quasi-canonical lifting to characteristic 0, and that for any such lifting, the endormorphism algebra of the transcendental cycles, as a Hodge module, is a CM field. The Tate conjecture for the product of certain two K3 surfaces is also proved. We illustrate by examples how to determine explicitly the formal Brauer group associated to a K3 surface over k. Examples discussed here are all of hypergeometric type.
研究了有限域上定义的K3曲面的算法。特别地,我们证明了在特征为p > 3的有限域k上的任何有限高度的K3曲面具有到特征0的拟正则提升,并且对于任何这样的提升,超越环的内模代数作为Hodge模是一个CM域。证明了两个K3曲面积的Tate猜想。我们举例说明如何明确地确定与k上的K3曲面相关的形式Brauer群。这里讨论的例子都是超几何型的。
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引用次数: 10
A sequence of blowing-ups connecting moduli of sheaves and the Donaldson Polynomial under change of polarization 极化变化下轮轴模与Donaldson多项式的一串爆破
Q2 Mathematics Pub Date : 2007-04-22 DOI: 10.1215/KJM/1250281738
Kimiko Yamada
Let $H$ and $H'$ be two ample line bundles over a nonsingular projective surface $X$, and $M(H)$ (resp. $M(H')$) the coarse moduli scheme of $H$-semistable (resp. $H'$-semistable) sheaves of fixed type $(r=2,c_1,c_2)$. In a moduli-theoretic way that comes from elementary transforms, we connect $M(H)$ and $M(H')$ by a sequence of blowing-ups when walls separating $H$ and $H'$ are not necessarily good. As an application, we also consider the polarization change problem of Donaldson polynomials.
设$H$和$H'$为非奇异投影曲面$X$上的两个充足的线束,$M(H)$ (p。$M(H')$), $H$-半稳定的粗模格式。$H'$-半稳定)固定型$(r=2,c_1,c_2)$。当$H$和$H'$分隔的墙不一定很好时,我们用一种来自初等变换的模理论方法,通过一系列膨胀将$M(H)$和$M(H')$连接起来。作为应用,我们还考虑了Donaldson多项式的极化变化问题。
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引用次数: 6
A global approach to the theory of special finsler manifolds 特殊finsler流形理论的全局方法
Q2 Mathematics Pub Date : 2007-03-31 DOI: 10.1215/KJM/1250271321
N. L. Youssef, S. H. Abed, A. Soleiman
The aim of the present paper is to provide a global presentation of the theory of special Finsler manifolds. We introduce and investigate globally (or in- trinsically, free from local coordinates) many of the most important and most com- monly used special Finsler manifolds: locally Minkowskian, Berwald, Landesberg, general Landesberg, P-reducible, C-reducible, semi-C-reducible, quasi-C-reducible, P ∗ -Finsler, C h -recurrent, C v -recurrent, C 0 -recurrent, S v -recurrent, S v -recurrent of the second order, C2-like, S3-like, S4-like, P2-like, R3-like, P-symmetric, h-isotropic, of scalar curvature, of constant curvature, of p-scalar curvature, of s-ps-curvature. The global definitions of these special Finsler manifolds are introduced. Various relationships between the different types of the considered special Finsler manifolds are found. Many local results, known in the literature, are proved globally and several new results are obtained. As a by-product, interesting identities and properties concerning the torsion tensor fields and the curvature tensor fields are deduced. Although our investigation is entirely global, we provide; for comparison rea- sons, an appendix presenting a local counterpart of our global approach and the local definitions of the special Finsler spaces considered. 1
本文的目的是提供特殊的芬斯勒流形理论的一个全局表示。我们从全局(或者从本质上讲,不依赖于局部坐标)引入和研究了许多最重要和最常用的特殊Finsler流形:局部minkowski, Berwald, Landesberg,一般Landesberg, P-可约,C-可约,半C-可约,拟C-可约,P * -Finsler, C h-递归,C v -递归,C 0 -递归,S v -递归,S v -二阶递归,c2类,s3类,s4类,p2类,r3类,P对称,h各向同性,标量曲率,常数曲率,P-标量曲率,S -ps曲率。给出了这些特殊的Finsler流形的全局定义。发现了不同类型的特殊芬斯勒流形之间的各种关系。许多文献中已知的局部结果得到了全局证明,并获得了一些新的结果。作为一个副产品,我们推导出了关于扭转张量场和曲率张量场的有趣的恒等式和性质。虽然我们的调查完全是全球性的,但我们提供;为了便于比较,在附录中给出了我们的全局方法的局部对应物和所考虑的特殊Finsler空间的局部定义。1
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引用次数: 27
The group homology and an algebraic version of the zero-in-the-spectrum conjecture 群同调和谱中零猜想的代数版本
Q2 Mathematics Pub Date : 2007-03-23 DOI: 10.1215/KJM/1250281050
Shin-ichi Oguni
We introduce an algorithm which transforms a finitely presented group G into another one G Ψ . By using this, we can get many finitely presented groups whose group homology with coefficients in the group von Neumann algebra vanish, that is, many counterexamples to an algebraic version of the zero-in-the-spectrum conjecture. Moreover we prove that the Baum-Connes conjecture does not imply the algebraic version of the zero-in-the-spectrum conjecture for finitely presented groups. Also we will show that for any p ≥ 3 the p -th group homology of G Ψ coming from free groups has infinite rank.
我们介绍了一种将有限呈现群G转化为另一个有限呈现群G的算法Ψ。利用这一点,我们可以得到许多有限呈现的群,这些群与群von Neumann代数中系数的群同源性消失,即谱中零猜想的代数版本的许多反例。此外,我们证明了对于有限呈现群,Baum-Connes猜想并不蕴涵谱中零猜想的代数版本。并证明了对于任意p≥3,来自自由群的G Ψ的p -群同调具有无穷秩。
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引用次数: 1
Fujita’s approximation theorem in positive charactristics 正性质下的藤田近似定理
Q2 Mathematics Pub Date : 2007-03-23 DOI: 10.1215/KJM/1250281075
S. Takagi
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引用次数: 29
Instructive examples of smooth complex differentiable and complex analytic mappings into locally convex spaces 局部凸空间的光滑复可微映射和复解析映射的指导性例子
Q2 Mathematics Pub Date : 2007-01-06 DOI: 10.1215/KJM/1250281028
Helge Glöckner
For each positive integer k, we describe a map f from the complex plane to a suitable non-complete complex locally convex space such that f is k times continuously complex differentiable but not k+1 times, and hence not complex analytic. We also describe a complex analytic map from l^1 to a suitable complete complex locally convex space which is unbounded on each non-empty open subset of l^1. Furthermore, we present a smooth map from the real line to a non-complete locally convex space which is not real analytic although it is given locally by its Taylor series around each point. As a byproduct, we find that free locally convex spaces over subsets of the complex plane with non-empty interior are not Mackey complete.
对于每一个正整数k,我们描述了一个从复平面到合适的非完全复局部凸空间的映射f,使得f是k次连续复可微,但不是k+1次,因此不是复解析的。我们还描述了从l^1到合适的完全复局部凸空间的复解析映射,该空间在l^1的每个非空开子集上是无界的。进一步,我们给出了实线到非完全局部凸空间的光滑映射,该映射虽然由其围绕每个点的泰勒级数局部给出,但不是实解析空间。作为副产物,我们发现复平面子集上具有非空内部的自由局部凸空间不是麦基完全的。
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引用次数: 4
Exact controllability of a Timoshenko beam with dynamical boundary 具有动力边界的Timoshenko光束的精确可控性
Q2 Mathematics Pub Date : 2007-01-01 DOI: 10.1215/KJM/1250281029
Chun-guo Zhang, Hongrui Hu
We consider the exact controllability of a Timoshenko beam system, clamped at one end and attached at the other end to a rigid antenna. Such a system is governed by two partial differential equations and two ordinary differential equations. Using the HUM method, we show that the system is exactly controllable in the usual energy space.
我们考虑了铁木辛科波束系统的精确可控性,该系统一端夹紧,另一端连接到刚性天线上。这样一个系统由两个偏微分方程和两个常微分方程控制。利用HUM方法,我们证明了系统在通常的能量空间是完全可控的。
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引用次数: 7
A remark on pseudoconvex domains with analytic complements in compact Kähler manifolds 紧Kähler流形中具有解析补的伪凸域的注释
Q2 Mathematics Pub Date : 2007-01-01 DOI: 10.1215/KJM/1250281070
T. Ohsawa
For an effective divisor A with support B in a compact K¨ahler manifold M of dimension ≥ 3, the following are antinomic. a) M B has a C ∞ plurisubharmonic exhaustion function whose Levi form has pointwise at least 3 positive eigenvalues outside a compact subset of M B . b) [ A ] | B , the normal bundle of A , is topologically trivial.
对于维数≥3的紧化K¨ahler流形M中具有支撑点B的有效因子A,下列是反律的。a) M B具有一个C∞多次调和耗尽函数,其Levi形式在M B的紧子集外点方向上至少有3个正特征值。b) [A] | A的正规束b是拓扑平凡的。
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引用次数: 15
On the bounded condition of an o-minimal structure 关于o-极小结构的有界条件
Q2 Mathematics Pub Date : 2007-01-01 DOI: 10.1215/kjm/1250281074
M. Kageyama
We will show that the theory of ordered divisible vector spaces over an ordered field satisfies the bounded condition treated in [5].
我们将证明有序域上有序可分向量空间的理论满足[5]中处理的有界条件。
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引用次数: 0
Characters of wreath products of compact groups with the infinite symmetric group and characters of their canonical subgroups 具有无限对称群的紧群环积的性质及其正则子群的性质
Q2 Mathematics Pub Date : 2007-01-01 DOI: 10.1215/KJM/1250281047
T. Hirai, E. Hirai
Characters of wreath products G = S∞(T ) of any compact groups T with the infinite symmetric group S∞ are studied. It is proved that the set E(G) of all normalized characters is equal to the set F (G) of all normalized factorizable continuous positive definite class functions. A general explicit formula of fA ∈ E(G) is given corresponding to a parameter A = “ (αζ,ε)(ζ,ε)∈ b T×{ 0,1 } ; μ ” . Similar results are obtained for certain canonical subgroups of G. Introduction Let S∞(T ) = S∞ D∞(T ) be the wreath product of a compact group T with the infinite symmetric group S∞, where D∞(T ) = ∏′ i∈NTi is the restricted direct product of Ti = T . In this paper we give explicitly characters of all the factor representations of finite type of S∞(T ), and give a general character formula. Since a character determines a quasi-equivalence class of factor representations of finite type, we have thus classified all such quasiequivalence classes. Let us explain in more detail. 1. For a Hausdorff topological group G, denote by K(G) the set of all continuous positive definite class functions on G, and by K≤1(G) and K1(G) the sets of f ∈ K(G) satisfying respectively f(e) ≤ 1 and f(e) = 1 at the identity element e ∈ G. Let E(G) = Extr(K1(G)) be the set of extremal points of the convex set K1(G). Then a character of a factor representation of finite type of G is canonically in 1-1 correspondence with an f ∈ E(G) (Theorem 1.1 quoted from [HH5]), and we call elements in E(G) characters of G. This is our background. 2. Let N be a subgroup of G with the relative topology, and denote by K1(N,G) the set of functions in K(N) invariant under G and put E(N,G) = Extr(K1(N,G)). Then the restriction of an f ∈ E(G) is always in E(N,G) 2000 Mathematics Subject Classification(s). Primary 20C32; Secondary 20C15, 20E22, 22A25, 22C05, 43A35 Received December 19, 2005 270 Takeshi Hirai and Etsuko Hirai (Theorem 1.3(i)). A kind of converse assertion is also assured in a certain restricted case containing the case of G = S∞(T ) and its canonical subgroups N (Theorem 1.3(ii)). A proof of the former assertion in the general setting is given in Section 14 (Theorem 14.1), and another proof for the converse assertion in the case of G = S∞(T ) is given in Section 15 (Theorem 15.1). These results assure that E(N) is obtained from E(G) by restriction for G = S∞(T ) and its canonical subgroups N . 3. From now on, let G = S∞(T ). An element g ∈ G is a pair (d, σ) of d = (ti)i∈N ∈ D∞(T ) with ti ∈ Ti = T and σ ∈ S∞. Then we put supp(d) = {i ∈N ; ti = eT } and supp(g) = supp(d)∪supp(σ), where eT denotes the identity element of T . An f ∈ K(G) is called factorizable if f(g1g2) = f(g1)f(g2) for any g1, g2 ∈ G with disjoint supports. Let F (G) be the set of all factorizable f ∈ K1(G). Then we prove E(G) ⊂ F (G) (Lemma 4.1) and E(G) ⊃ F (G) (Lemma 4.4), and so E(G) = F (G). In the case of a finite group T , these inclusions were both proved by using the fact that the convex set K≤1(G) is compact in the
研究了具有无限对称群S∞的任意紧群T的环积G = S∞(T)的性质。证明了所有归一化字符的集合E(G)等于所有归一化可分解连续正定类函数的集合F (G)。给出了fA∈E(G)对应于参数A = " (αζ,ε)(ζ,ε)∈b tx {0,1};μ”。引入设S∞(T) = S∞D∞(T)是紧群T与无限对称群S∞的环积,其中D∞(T) =∏′i∈NTi是Ti = T的限制直积。本文给出了S∞(T)有限型的所有因子表示的显式性质,并给出了一般性质公式。由于一个字符决定了有限类型因子表示的拟等价类,因此我们对所有这些拟等价类进行了分类。让我们更详细地解释一下。1. 对于Hausdorff拓扑群G,用K(G)表示G上所有连续正定类函数的集合,用K≤1(G)和K1(G)表示f∈K(G)在单位元e∈G处分别满足f(e)≤1和f(e) = 1的集合,设e (G) = Extr(K1(G))为凸集K1(G)的极值点的集合。那么,有限类型G的因子表示的一个字符与f∈E(G)通常是1-1对应关系(引自[HH5]的定理1.1),我们称E(G)中的元素为G的字符。2. 设N是具有相对拓扑的G的一个子群,用K1(N,G)表示K(N)中的函数集合在G下不变,令E(N,G) = Extr(K1(N,G))。那么在E(N,G) 2000数学学科分类(s)中,f∈E(G)的约束总是存在的。主要20 c32;第二期20C15, 20E22, 22A25, 22C05, 43A35收到2005年12月19日270 Takeshi Hirai, Etsuko Hirai(定理1.3(i))。在包含G = S∞(T)及其正则子群N的特定限制情况下,也保证了一类逆断言(定理1.3(ii))。第14节(定理14.1)给出了前一个命题在一般情况下的证明,第15节(定理15.1)给出了G = S∞(T)情况下逆命题的另一个证明。这些结果保证了E(N)是通过对G = S∞(T)及其正则子群N的限制而由E(G)得到的。3.从现在起,令G = S∞(T)。元素g∈g是d = (ti)i∈N∈d∞(T)且ti∈ti = T且σ∈S∞的一对(d, σ)。令supp(d) = {i∈N;ti = eT}, supp(g) = supp(d)∪supp(σ),其中eT表示T的单位元。对于任意具有不相交支撑的g1, g2∈G,如果f(g1g2) = f(g1)f(g2),则f∈K(G)是可分解的。设F (G)为所有可分解的F∈K1(G)的集合。然后我们证明E(G)∧F (G)(引理4.1)和E(G)、F (G)(引理4.4),因此E(G) = F (G)。在有限群T的情况下,利用凸集K≤1(G)在弱拓扑σ(L∞(G), L(G))中紧化这一事实证明了这些包含(cf. [HH3])。但在无限紧群T的情况下,引理4.1和4.4的证明都与[HH3]中的证明不同。4. 为了得到f∈E(G)的所有字符,我们进行如下操作。首先,取G上的一个简单正定函数F和紧子群的一个递增序列GN * G。取F关于GN的中心化FN为FN (g) =∫GN F (g ' gg ') dμGN (g ') (g∈g),其中μGN表示GN上的归一化Haar测度。然后考虑逐点极限f = limN→∞FN。如果它作为连续函数存在,则它在G下是正定不变的,因此f∈K1(G)。作为这个过程的起点,我们取初等诱导表示ρ = IndHπ (G)的对角矩阵元素F,它是子群H或类似子群的幺正表示π。选择{GN}N≥1和(π,H),我们实际上可以得到一大族的归一化可分解正定类函数fA依赖于一个参数a = ((αζ,ε)(ζ,ε)∈b tx {0,1};μ),由{GN}N≥1的渐近数据和(π,H)的数据确定。设E ' (G)是所有这些fA的集合。E ' (G)∧F (G)。这一过程在第9-12节中进行,与[HH3]中有限群T的情况类似。5. 在第13节中,我们研究了一个可分解的f∈f (G)如何依赖于一组参数。对f在G = D∞(T) S∞上对Dn(T)进行偏傅里叶变换,我们得到一系列正定的类函数f ζ,ε,n(f)在Sn上,n≥2。然后,将Korollar 1推广到[Tho2]中的Satz 2,我们可以证明F (G)∧E ' (G),因此F (G) = E ' (G)(定理13.1)。由此得到E ' (G) = F (G) = E(G)为集合,并得到了对G的任意字符都有效的一般显式字符公式。 进一步地,通过G的这种显式参数化,我们看到了E(G)在紧一致收敛的拓扑τcu上是紧的(紧群与无限对称群的环积的定理性质271 13.2)。6. 在第14-16节中,我们还研究了G = S∞(T)的正则子群的情况,如G ' = A∞(T),当T是阿贝尔时,如G = S∞(T)和G ' S = A∞(T)对于T的闭子群S,它们在第2节中定义。为了从G的结果中得到这些子群的所有特征,我们给出了一个正则子群约简的一般定理。设G是一个拓扑群,N是它的正规子群。用K1(N,G)表示N上归一化为f(e) = 1的G不变的连续正定函数集,用e (N,G):= Extr(K1(N,G))表示凸集K1(N,G)的极值点集。定理14.1。设G为一个Hausdorff拓扑群,N为其具有相对拓扑的正规子群。(i)对于F∈K1(G),设F = F |N为其对N的限制。它属于K1(N,G),若f = a1f1 + a2f2且ai > 0, fi∈K1(N,G),则对于i = 1,2, fi存在扩展fi∈K1(G),使得f = a1f1 + a2f2。(ii)对于任意F∈E(G),其约束F = F |N属于E(N,G)。对于G = S∞(T),设N为G的上述正则子群之一。然后K1(N,G) = K1(N)所以E(N,G) = E(N)因此定理14.1断言限制E(G) F→F = F |N将E(G)映射到E(N)。7. 本文的组织结构如下。经过第2-3节对G = S∞(T)及其正则子群的若干准备,在定理5.1中给出了G的特征fA的显式公式。当紧群T是阿贝尔时,公式采用定理6.1中给出的稍微简单的形式。定理7.1给出了G的正则子群G的特征公式。这些定理的证明方法将在第8节中解释。第9-13节主要用于证明定理5.1和6.1。第14-16节专门讨论G. 8的正则子群的情况。无限对称群S∞本身的所有性质早在[Tho2]中就已经给出,在[VeKe]、[Oko]、[KeOl]、[Bia]等文献中以及最近的[Hir3] - [Hir4]文献中都重新检验了这种情况。[HH1]中研究的有限阿贝尔群T的情况,包含了无限Weyl群WB∞和WD∞的情况,以及复反射群的极限S∞(Zr) = limn→∞G(r, 1, n)。在[HH2] - [HH3]中给出了S∞(T)与T任意有限群的情况和离散情况。
{"title":"Characters of wreath products of compact groups with the infinite symmetric group and characters of their canonical subgroups","authors":"T. Hirai, E. Hirai","doi":"10.1215/KJM/1250281047","DOIUrl":"https://doi.org/10.1215/KJM/1250281047","url":null,"abstract":"Characters of wreath products G = S∞(T ) of any compact groups T with the infinite symmetric group S∞ are studied. It is proved that the set E(G) of all normalized characters is equal to the set F (G) of all normalized factorizable continuous positive definite class functions. A general explicit formula of fA ∈ E(G) is given corresponding to a parameter A = “ (αζ,ε)(ζ,ε)∈ b T×{ 0,1 } ; μ ” . Similar results are obtained for certain canonical subgroups of G. Introduction Let S∞(T ) = S∞ D∞(T ) be the wreath product of a compact group T with the infinite symmetric group S∞, where D∞(T ) = ∏′ i∈NTi is the restricted direct product of Ti = T . In this paper we give explicitly characters of all the factor representations of finite type of S∞(T ), and give a general character formula. Since a character determines a quasi-equivalence class of factor representations of finite type, we have thus classified all such quasiequivalence classes. Let us explain in more detail. 1. For a Hausdorff topological group G, denote by K(G) the set of all continuous positive definite class functions on G, and by K≤1(G) and K1(G) the sets of f ∈ K(G) satisfying respectively f(e) ≤ 1 and f(e) = 1 at the identity element e ∈ G. Let E(G) = Extr(K1(G)) be the set of extremal points of the convex set K1(G). Then a character of a factor representation of finite type of G is canonically in 1-1 correspondence with an f ∈ E(G) (Theorem 1.1 quoted from [HH5]), and we call elements in E(G) characters of G. This is our background. 2. Let N be a subgroup of G with the relative topology, and denote by K1(N,G) the set of functions in K(N) invariant under G and put E(N,G) = Extr(K1(N,G)). Then the restriction of an f ∈ E(G) is always in E(N,G) 2000 Mathematics Subject Classification(s). Primary 20C32; Secondary 20C15, 20E22, 22A25, 22C05, 43A35 Received December 19, 2005 270 Takeshi Hirai and Etsuko Hirai (Theorem 1.3(i)). A kind of converse assertion is also assured in a certain restricted case containing the case of G = S∞(T ) and its canonical subgroups N (Theorem 1.3(ii)). A proof of the former assertion in the general setting is given in Section 14 (Theorem 14.1), and another proof for the converse assertion in the case of G = S∞(T ) is given in Section 15 (Theorem 15.1). These results assure that E(N) is obtained from E(G) by restriction for G = S∞(T ) and its canonical subgroups N . 3. From now on, let G = S∞(T ). An element g ∈ G is a pair (d, σ) of d = (ti)i∈N ∈ D∞(T ) with ti ∈ Ti = T and σ ∈ S∞. Then we put supp(d) = {i ∈N ; ti = eT } and supp(g) = supp(d)∪supp(σ), where eT denotes the identity element of T . An f ∈ K(G) is called factorizable if f(g1g2) = f(g1)f(g2) for any g1, g2 ∈ G with disjoint supports. Let F (G) be the set of all factorizable f ∈ K1(G). Then we prove E(G) ⊂ F (G) (Lemma 4.1) and E(G) ⊃ F (G) (Lemma 4.4), and so E(G) = F (G). In the case of a finite group T , these inclusions were both proved by using the fact that the convex set K≤1(G) is compact in the","PeriodicalId":50142,"journal":{"name":"Journal of Mathematics of Kyoto University","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66089014","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 5
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Journal of Mathematics of Kyoto University
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