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991.
Narayan C. Giri 《Annals of the Institute of Statistical Mathematics》1988,40(2):381-394
In this paper we give an extension of the theory of local minimax property of Giri and Kiefer (1964, Ann. Math. Statist., 35, 21–35) to the family of elliptically symmetric distributions which contains the multivariate normal distribution as a member.This work was partially supported by the Canadian N.S.E.R.C. grant 相似文献
992.
An almost contact metric structure is parametrized by a section σ of an associated homogeneous fibre bundle, and conditions
for σ to be a harmonic section, and a harmonic map, are studied. These involve the characteristic vector field ξ, and the
almost complex structure in the contact subbundle. Several examples are given where the harmonic section equations for σ reduce
to those for ξ, regarded as a section of the unit tangent bundle. These include trans-Sasakian structures. On the other hand,
there are examples where ξ is harmonic but σ is not a harmonic section. Many examples arise by considering hypersurfaces of
almost Hermitian manifolds, with the induced almost contact structure, and comparing the harmonic section equations for both
structures.
相似文献
993.
In this work, we introduce and study a class of generalized vector equilibrium problems for multifunctions which includes a number of generalized vector variational inequality problems and generalized vector variational-like inequality problems as special cases. By using the KKM–Fan theorem and Nadler’s result, we prove an existence theorem for solutions for this class of generalized vector equilibrium problems in Banach spaces. Applications to generalized vector variational-like inequalities are given. 相似文献
994.
FAN Hong-Yi TANG Xu-Bing 《理论物理通讯》2006,46(10)
Based on the invariant eigen-operator method (IEO) [Phys. Lett. A 321 (2004) 75] we derive the exact energy gap for some Hamiltonians, which describe some polariton systems. The result shows that in some cases the IEO method, stemming from the Heisenberg approach, is more direct and convenient for deriving the energy-level gap formula than via the approach of solving the Schr(o)dinger equation. 相似文献
995.
In this paper, we investigate the isolated closed orbits of two types of cubic vector fields in R3 by using the idea of central projection transformation, which sets up a bridge connecting the vector field X(x) in R3 with the planar vector fields. We have proved that the cubic vector field in R3 can have two isolated closed orbits or one closed orbit on the invariant cone. As an application of this result, we have shown that a class of 3-dimensional cubic system has at least 10 isolated closed orbits located on 5 invariant cones, and another type of 3-dimensional cubic system has at least 26 isolated closed orbits located on 13 invariant cones or 26 invariant cones. 相似文献
996.
本文讨论了度量空间上一个连续自映射击一点处的迭代序列的子列极限点集的结构,所得的结果统一和推广了Diaz和Metcalf,Maiti和Babu和Park的若干结果. 相似文献
997.
A. Lechicki 《Journal of Mathematical Analysis and Applications》2004,297(2):751-770
We study a family of convergences (actually pretopologies) in the hyperspace of a metric space that are generated by covers of the space. This family includes the Attouch-Wets, Fell, and Hausdorff metric topologies as well as the lower Vietoris topology. The unified approach leads to new developments and puts into perspective some classical results. 相似文献
998.
We review the relativistic classical and quantum mechanics of Stueckelberg, and introduce the compensation fields necessary for the gauge covariance of the Stueckelbert–Schrödinger equation. To achieve this, one must introduce a fifth, Lorentz scalar, compensation field, in addition to the four vector fields with compensate the action of the space-time derivatives. A generalized Lorentz force can be derived from the classical Hamilton equations associated with this evolution function. We show that the fifth (scalar) field can be eliminated through the introduction of a conformal metric on the spacetime manifold. The geodesic equation associated with this metric coincides with the Lorentz force, and is therefore dynamically equivalent. Since the generalized Maxwell equations for the five dimensional fields provide an equation relating the fifth field with the spacetime density of events, one can derive the spacetime event density associated with the Friedmann–Robertson–Walker solution of the Einstein equations. The resulting density, in the conformal coordinate space, is isotropic and homogeneous, decreasing as the square of the Robertson–Walker scale factor. Using the Einstein equations, one see that both for the static and matter dominated models, the conformal time slice in which the events which generate the world lines are contained becomes progressively thinner as the inverse square of the scale factor, establishing a simple correspondence between the configurations predicted by the underlying Friedmann–Robertson–Walker dynamical model and the configurations in the conformal coordinates. 相似文献
999.
In this paper we study the possibility of globally stabilizinginvariant sets of autonomous continuous nonlinear systems bythe state (output) feedback control law. We show that the topologicalstructure of invariant sets can give rise to obstruction tothe existence of a continuous control law for global stabilizationof invariant sets. 相似文献
1000.
Continued fractions w.r.t. a specified class of numbers is considered. The invariant measures of the corresponding transformations are identified connecting the continued fractions with geodesics on the upper half plane. A problem of convergence in distribution of sums of the coefficients of the continued fraction is also considered. 相似文献