排序方式: 共有51条查询结果,搜索用时 15 毫秒
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In [5] Phillips proved that one can obtain the additive group of any nonstandard model *? of the ring ? of integers by using a linear mod 1 function h : F ?, where F is the α-dimensional vector space over ? when α is the cardinality of *?. In this connection it arises the question whether there are linear mod 1 functions which are neither addition nor quasi-linear. We prove that this is the case. 相似文献
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Chandrashekhar Khare 《Compositio Mathematica》1998,112(3):365-378
Given an irreducible, modular, mod p representation p, we analyse the local components at p of newforms f which give rise to it. 相似文献
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基于Karhunen-Loève变换和小波谱特征矢量量化的三维谱像数据压缩 总被引:1,自引:1,他引:0
提出了基于Karhunen Lo埁ve变换的小波谱特征矢量量化三维谱像数据压缩方法耍幔颍瑁酰睿澹?Lo埁ve变换 /小波变换 /小波谱特征矢量量化方法应用了Karhunen Lo埁ve变换的消除谱相关性优良性能 ,应用二维小波变换消除空间相关性 ,在小波变换域内应用二维集分割嵌入块编码和一维谱特征矢量量化对三维谱像数据压缩 ,获得较高的压缩性能。实验结果表明 :Karhunen Lo埁ve变换 /小波变换 /小波谱特征矢量量化编码比Karhunen Lo埁ve变换 /小波变换 /改进对块零树编码和Karhunen Lo埁ve变换 /小波变换 /快速矢量量化编码方法在同样压缩比条件下 ,峰值信噪比提高 2dB和 1dB以上 ,而速度提高了 1.5和 8倍 ,整体压缩性能有较大的提高 相似文献
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ZHANG WEIPING 《数学年刊B辑(英文版)》2005,26(1)
The author presents an alternate proof of the Bismut-Zhang localization formula of ηinvariants, when the target manifold is a sphere, by using ideas of mod k index theory instead of the difficult analytic localization techniques of Bismut-Lebeau. As a consequence, it is shown that the R/Z part of the aualytically defined η invariant of Atiyah-Patodi-Singer for a Dirac operator on an odd dimensional closed spin manifold can be expressed purely geometrically through a stable Chern-Simons current on a higher dimensional sphere. As a preliminary application, the author discusses the relation with the Atiyah-Patodi-Singer R/Z index theorem for unitary flat vector bundles,and proves an R refinement in the case where the Dirac operator is replaced by the Signature operator. 相似文献
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For the Monge-Ampere equation det D2u = 1, the authors find new auxiliary curvature functions which attain their respective maxima on the boundary. Moreover, the upper bounded estimates for the Gauss curvature and the mean curvature of the level sets for the solution to this equation are obtained. 相似文献
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Let $\hat \mathbb{Z}$ denote the inverse limit of all finite cyclic groups. Let F, G and H be abelian groups with H ≤ G. Let FβH denote the abelian group (F × H, +β), where +βis defined by (a, x) +β (b, y) = (a + b, x + y + β(a) + β(b) — β(a + b)) for a certain β : F → G linear mod H meaning that β(0) = 0 and β(a) + β(b) — β(a + b) ∈ H for all a, b in F. In this paper we show that the following hold: (1) The additive group of any nonstandard model ℤ* of the ring ℤ is isomorphic to (ℤ*+/H)βH for a certain β : ℤ*+/H → $\hat \mathbb{Z}$ linear mod H. (2) $\hat \mathbb{Z}$ is isomorphic to (ℤ+/H )βH for some β : $\hat \mathbb{Z}$/H →ℚ linear mod H, though $\hat \mathbb{Z}$ is not the additive group of any model of Th(ℤ, +, ×) and the exact sequence H → $\hat \mathbb{Z}$ → $\hat \mathbb{Z}$/H is not splitting. 相似文献
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近年来拓扑学在量子力学中得到了广泛的运用.本文将安培环路定理积分式重新表达为一矢量场在轮胎参数面上的第一类陈数积分.数值模拟展示了该积分值为一整数即第一陈数,其代表矢量场的整体性质:当经历连续变换时,矢量场的局部数值发生改变但整体积分值即陈数仍保持不变;若陈数发生改变,则表明矢量场变换的连续性条件发生破坏,矢量场出现奇点.进一步通过高斯映射将该矢量场从参数轮胎面映射到单位球面上,并给出了第一陈数的直观几何意义.理论和数值结果揭示了安培环路定理的拓扑学本质,表明拓扑概念在经典物理学中也会有广泛应用. 相似文献