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141.
We analyze in detail projective modules over two-dimensional noncommutative tori and complex structures on these modules. We concentrate our attention on properties of holomorphic vectors in these modules; the theory of these vectors generalizes the theory of theta-functions. The paper is self-contained; it can be used also as an introduction to the theory of noncommutative spaces with simplest space of this kind thoroughly analyzed as a basic example. 相似文献
142.
Michael Ruzhansky Mitsuru Sugimoto Joachim Toft Naohito Tomita 《Mathematische Nachrichten》2011,284(16):2078-2092
In this paper various properties of global and local changes of variables as well as properties of canonical transforms are investigated on modulation and Wiener amalgam spaces. We establish several relations among localisations of such spaces and, as a consequence, we obtain several versions of local and global Beurling–Helson type theorems. We also establish a number of positive results such as local boundedness of canonical transforms on modulation spaces, properties of homogeneous changes of variables, and local continuity of Fourier integral operators on ${\mathscr F}L^q$. Finally, counterparts of these results are discussed for spaces on the torus. 相似文献
143.
Peter Stadler 《Journal of Difference Equations and Applications》2019,25(9-10):1382-1403
ABSTRACTWe can shorten any path that links two given points by applying short ruler transforms iteratively. In this article we take a closer look at a short ruler process on the torus. The torus is a compact Riemannian manifold and at least a subsequence of the process converges to a geodesic between the two points. However, on compact Riemann manifolds there might exist different limit geodesics (with the same length). On the torus, the geodesics with the same length are isolated and the limit geodesic is unique. 相似文献
144.
Fall of open tori horizontally dropped in quiescent water is experimentally investigated. The fall is controlled by the Galileo number, the torus aspect ratio and the solid to fluid density ratio. The dependence of the descent velocity and of the drag coefficient on the control parameters is first analyzed. As the control parameters are varied, vertical translation, zigzagging and spiraling descent are observed. These different descent modes are characterized and a phase diagram of the falling tori are presented as function of the three control parameters. 相似文献
145.
Mingzhong WU 《Frontiers of Mathematics in China》2015,10(3):697
We discuss a class of filiform Lie superalgebras Ln,m. From these Lie superalgebras, all the other filiform Lie superalgebras can be obtained by deformations. We have decompositions of D e r 0 ˉ (Ln,m) and D e r 1 (Ln,m). By computing a maximal torus on each Ln,m, we show that Ln,m are completable nilpotent Lie superalgebras. We also view Ln,m as Lie algebras, prove that Ln,m are of maximal rank, and show that Ln,m are completable nilpotent Lie algebras. As an application of the results, we show a Heisenberg superalgebra is a completable nilpotent Lie superalgebra. 相似文献
146.
An oscillator with dry friction under external excitation is considered.The Poincaré map can be established according to the series solution near equilibrium in the case of 1:4 resonance.Based on the theory of normal forms,the map is reduced into its normal form.It is shown that the Neimark-Sacker(N-S) bifurcations may occour.The theoretical results are verified with the numerical simulations. 相似文献
147.
XuSenlin DengQintao ChenDongmei 《分析论及其应用》2004,20(3):288-293
Let M be a compact minimal hypersurface of sphere Sn 1(1). Let (M) be H (r)-torus of sphere Sn 1 (1).Assume they have the same constant mean curvature H, the result in [1] is that ifSpec0(M, g) =Spec0((M), g),then for 3≤ n ≤ 6, r2≤n-1/n or n ≥ 6, r2 ≥ n-1, then M is isometric to (M). We improved the result and prove that: if Spec0(M,g) =Spec0((M),g), then M is isometric to (M). Generally, if Specp(M,g) =Specp((M),g), here p is fixed and satisfies that n(n - 1) ≠ 6p(n - p), then M is isometric to (M). 相似文献
148.
Conditions of creating an absolute magnetic trap for controllable thermonuclear fusion with the help of a high-current relativistic
beam of charged particles are considered. It is demonstrated that these conditions are realized for a compact beam torus (CBT)
in an intrinsic electromagnetic field. On the other hand, from the virial theorem it follows that for positive beam pressure
and positive energy density of the electromagnetic field, no strictly stationary state exists in the empty Minkowski flat
space-time.
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 75–78, February, 2009. 相似文献
149.
In this paper some exact expressions for the first and second Zagreb indices of graph operations containing the Cartesian product, composition, join, disjunction and symmetric difference of graphs will be presented. We apply some of our results to compute the Zagreb indices of arbitrary C4 tube, C4 torus and q-multi-walled polyhex nanotorus. 相似文献
150.
Rencai Lü 《数学年刊B辑(英文版)》2009,30(2):129-138
The author first constructs a Lie algebra ∑ :=∑(q, Wd) from rank 3 quantum torus, which is isomorphic to the core of EALAs of type Ad-1 with coordinates in quantum torus Cqd, and then gives the necessary and sufficient conditions for the highest weight modules to be quasifinite nonzero central charges are Finally the irreducible Z-graded quasifinite ∑-modules with classified. 相似文献