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All Lorentzian tori with a non-discrete group of isometries are characterized and explicitly obtained. They can lie into three cases: (a) flat, (b) conformally flat but non-flat, and (c) geodesically incomplete. A detailed study of many of their properties (including results on the logical dependence of the three kinds of causal completeness, on geodesic connectedness and on prescribed curvature) is carried out. The incomplete case is specially analyzed, and several known examples and results in the literature are generalized from a unified point of view.
64.
本文解决K.Tahara提出的猜想,给出了所有四维代数环群上全部无固定点的有理自同构群. 相似文献
65.
球环位形磁流体平衡的数值模拟 总被引:1,自引:1,他引:0
对原有的托卡马克平衡编码SWEQU进行了改进。使之适用于小环径比球形环装置的磁流体研究。用改进后的平衡编码SWEQU模拟了放电初始阶段等离子体平衡位形的演化及稳态阶段的双零偏滤器平衡位形。结果表明。不但町以得到球形环装置稳态阶段的平衡位形,也可以模拟等离子体电流上升阶段平衡位形的演化过程。 相似文献
66.
The SDIFF(T2)local-generalized Kac-Moody G(T2) symmetry is an infinite-dimensional group on the torus membrane, whose Lie algebra is the semi-direct sum of the SDIFF(T2)local algebra and the generalized KacMoody algebra g(T2). In this paper, we construct the linearly realized gauge theory of the SDIFF(T2)loc1al-generalized Kac-Moody G(T2) symmetry.`` 相似文献
67.
《Journal of separation science》2017,40(23):4619-4627
The ability of a method and instrument to separate very similar compounds is related to the “plate number,” a number indicating performance. The resolution between two neighboring peaks is proportional to the square root of the plate number. Currently available commercial capillary electrophoresis instruments easily reach plate numbers of a few million. In the present work, a capillary electrophoresis system with a toroidal platform is proposed and theoretically studied with the goal of extending the achievable plate number. In this new system, electrophoresis occurs in a nonstop continuous circulating mode within a closed loop capillary (toroid). Plate numbers upwards of one billion are theoretically predicted. This could resolve hundreds of unseparated mixtures of stereoisomers and other analytes that remain without a method for their analysis. 相似文献
68.
Bang-Yen Chen 《Annali di Matematica Pura ed Applicata》2006,185(4):555-576
The notion of contact number
of a Euclidean submanifold was introduced in an earlier article (Proc. Edinb. Math. Soc. 47:69–100, 2004) as the highest
order of contact of geodesics and normal sections on the submanifold. It was proved in (Proc. Edinb. Math. Soc. 47:69–100,
2004) that the contact number relates closely with the notions of isotropic submanifolds and holomorphic curves. One important
problem concerning contact number is to construct Euclidean submanifolds with high contact number. The purpose of this article
is thus to construct Euclidean surfaces with high contact number and to provide simple geometric characterization of such
surfaces.
Mathematics Subject Classification (2000) Primary 53C40, 53A10 Secondary 53B25, 53C42 相似文献
69.
Yusuf Civan 《Proceedings of the American Mathematical Society》2006,134(5):1537-1548
We study the enumeration problem of stably complex structures on bounded flag manifolds arising from omniorientations, and determine those induced by almost complex structures. We also enumerate the stably complex structures on these manifolds which bound, therefore representing zero in the complex cobordism ring .
70.
Igor Nikolaev 《Proceedings of the American Mathematical Society》2006,134(4):973-981
The ``noncommutative geometry' of complex algebraic curves is studied. As a first step, we clarify a morphism between elliptic curves, or complex tori, and -algebras , or noncommutative tori. The main result says that under the morphism, isomorphic elliptic curves map to the Morita equivalent noncommutative tori. Our approach is based on the rigidity of the length spectra of Riemann surfaces.