期刊文献+
共找到2,270篇文章
< 1 2 114 >
每页显示 20 50 100
Space Topologies and Their Dual Space Topologies for Conventional Functional Space Topologies
1
作者 Mahjoub A. Elamin 《Journal of Applied Mathematics and Physics》 2024年第3期778-804,共27页
In this paper, we have studied the topology of some classical functional spaces. Among these spaces, there are standard spaces, spaces that can be metrizable and others that cannot be metrizable. But they are all topo... In this paper, we have studied the topology of some classical functional spaces. Among these spaces, there are standard spaces, spaces that can be metrizable and others that cannot be metrizable. But they are all topological vector spaces and it is in this context that we have chosen to present this work. We are interested in the topology of its spaces and in the topologies of their dual spaces. The first part, we presented the fundamental topological properties of topological vector spaces. The second part, we studied Frechet spaces and particularly the space S(R<sup>n</sup>) of functions of class C<sup>∞ </sup>on R<sup>n</sup> which are as well as all their rapidly decreasing partial derivatives. We have also studied its dual S'(Rn</sup>) the space of tempered distributions. The last part aims to define a topological structure on an increasing union of Frechet spaces called inductive limit of Frechet spaces. We study in particular the space D(Ω) of functions of class C<sup>∞</sup> with compact supports on Ω as well as its dual D' (Ω) the space distributions over the open set Ω. 展开更多
关键词 Linear forms Dual spaces Frechet spaces Partial Derivatives DISTRIBUTIONS Topological Structure Weak Topology Strong Topology
下载PDF
SLANT IMMERSIONS OF COMPLEX SPACE FORMS AND CHEN'S INEQUALITY 被引量:10
2
作者 李光汉 吴传喜 《Acta Mathematica Scientia》 SCIE CSCD 2005年第2期223-232,共10页
A submanifold in a complex space form is called slant if it has constant Wirtinger angles. B. Y. Chen and Y. Tazawa proved that there do not exist minimal proper slant surfaces in CP2 and CH2. So it seems that the sla... A submanifold in a complex space form is called slant if it has constant Wirtinger angles. B. Y. Chen and Y. Tazawa proved that there do not exist minimal proper slant surfaces in CP2 and CH2. So it seems that the slant immersion has some interesting properties. The authors have great interest to consider slant immersions satisfying some additional conditions, such as unfull first normal bundles or Chen’s equality holding. They prove that there do not exist n-dimensional Kaehlerian slant immersions in CPn and CHn with unfull first normal bundles. Next, it is seen that every Kaehlerian slant submanifold satisfying an equality of Chen is minimal which is similar to that of Lagrangian immersions. But in contrast, it is shown that a large class of slant immersions do not exist thoroughly. Finally, they give an application of Chen’s inequality to general slant immersions in a complex projective space, which generalizes a result of Chen. 展开更多
关键词 Slant immersion IDEAL Chen's inequality complex space form
下载PDF
On Intrinsic Rigidity for Submanifolds with Constant Scalar Curvature in Space Forms 被引量:1
3
作者 陈伟 郭震 《Northeastern Mathematical Journal》 CSCD 2007年第3期200-214,共15页
Under the assumption that the normalized mean curvature vector is parallel in the normal bundle, by using the generalized ChengYau's self-adjoint differential operator, here we obtain some rigidity results for compac... Under the assumption that the normalized mean curvature vector is parallel in the normal bundle, by using the generalized ChengYau's self-adjoint differential operator, here we obtain some rigidity results for compact submanifolds with constant scalar curvature and higher codimension in the space forms. 展开更多
关键词 space form scalar curvature differential operator RIGIDITY
下载PDF
The Architectural Expression of Space and Form Created by the Light in the Works of Alvaro Siza 被引量:1
4
作者 Chang Sung Kim Kyung Wook Seo 《Journal of Building Construction and Planning Research》 2014年第2期118-131,共14页
The light is an important element which helps people perceive objects. Therefore, it is important for architects to make the light and space be in harmony with each other. In this study, we analyzed the works of Alvar... The light is an important element which helps people perceive objects. Therefore, it is important for architects to make the light and space be in harmony with each other. In this study, we analyzed the works of Alvaro Siza with a view to understand the conceptual value of the light expressed in his works and his principles in controlling it. According to the results of the study, the Siza’s architecture is not a mere theoretical one trapped inside formality, but is a sensual and experiential one based on the locality. He was willing to use void spaces to invite the light in free-flowing plans, in order to invigorate and extend architectural spatiality to create deeper visual effect. In addition, the refined light in his works helped visitors experience the continuous forms and spaces by their own movements, while using the changes of the light to stimulate the interest of visitors and highlight the sequence of spaces. 展开更多
关键词 Alvaro Siza LIGHT form space
下载PDF
Forming of Space Charge Wave with Broad Frequency Spectrum in Helical Relativistic Two-Stream Electron Beams 被引量:1
5
作者 A.Lysenko I.Volk +1 位作者 A.Serozhko O.Rybalko 《Chinese Physics Letters》 SCIE CAS CSCD 2017年第7期150-154,共5页
We elaborate a quadratic nonlinear theory of plural interactions of growing space charge wave (SCW) harmonics during the development of the two-stream instability in helical relativistic electron beams. It is found ... We elaborate a quadratic nonlinear theory of plural interactions of growing space charge wave (SCW) harmonics during the development of the two-stream instability in helical relativistic electron beams. It is found that in helical two-stream electron beams the growth rate of the two-stream instability increases with the beam entrance angle. An SCW with the broad frequency spectrum, in which higher harmonics have higher amplitudes, forms when the frequency of the first SCW harmonic is much less than the critical frequency of the two-stream instability. For helical electron beams the spectrum expands with the increase of the beam entrance angle. Moreover, we obtain that utilizing helical electron beams in multiharmonic two-stream superheterodyne free-electron lasers leads to the improvement of their amplification characteristics, the frequency spectrum broadening in multiharmonic signal generation mode, and the reduction of the overall system dimensions. 展开更多
关键词 SCW forming of space Charge Wave with Broad Frequency Spectrum in Helical Relativistic Two-Stream Electron Beams
下载PDF
Some Inequalities for Submanifolds in Cosymplectic Space Forms 被引量:1
6
作者 LI Xing-xiao HUANG Guang-yue 《Chinese Quarterly Journal of Mathematics》 CSCD 北大核心 2005年第4期372-379,共8页
For submanifolds in a cosymplectic space form tangent to the structure vector field ξ, two important inequalities with Ricci curvature, scalar curvature and the squared mean curvature are obtained. These results are ... For submanifolds in a cosymplectic space form tangent to the structure vector field ξ, two important inequalities with Ricci curvature, scalar curvature and the squared mean curvature are obtained. These results are also applied to get corresponding consequences for anti-invariant submanifolds. 展开更多
关键词 余辛空间 子流形 不等式 空间形式
下载PDF
HYPERSURFACES IN SPACE FORMS WITH SCALAR CURVATURE CONDITIONS
7
作者 徐森林 张运涛 《Acta Mathematica Scientia》 SCIE CSCD 2004年第1期39-44,共6页
Let f: Mn(?)Sn+1 C Rn+2 be an n-dimensional complete oriented Rieman-nian manifold minimally immersed in an (n+1)-dimensional unit sphere Sn+1. Denote by S_+~n+1 the upper closed hemisphere. If f(Mn)(?)_+~n+1, then un... Let f: Mn(?)Sn+1 C Rn+2 be an n-dimensional complete oriented Rieman-nian manifold minimally immersed in an (n+1)-dimensional unit sphere Sn+1. Denote by S_+~n+1 the upper closed hemisphere. If f(Mn)(?)_+~n+1, then under some curvature conditions the authors can get that the isometric immersion is a totally embedding. They also generalize a theorem of Li Hai Zhong on hypersurface of space form with costant scalar curvature. 展开更多
关键词 HYPERSURFACE scalar curvature space form
下载PDF
Form Invariance, Noether and Lie Symmetry of Non-conservative Hamiltonian Systems in Phase Space
8
作者 傅景礼 陈立群 谢凤萍 《Journal of Shanghai University(English Edition)》 CAS 2004年第3期252-257,共6页
For the non-conservative holonomic Hamiltonian systems in phase space, the definition and criteria of the form invariance of the generalized Hamilton canonical equations were given. The relations among the form invari... For the non-conservative holonomic Hamiltonian systems in phase space, the definition and criteria of the form invariance of the generalized Hamilton canonical equations were given. The relations among the form invariance, Noether symmetry and Lie symmetry were studied. The theory of the form invariance for the conservative holonomical systems was worked out. An example was given to illustrate the results. 展开更多
关键词 form invariance Noether symmetry Lie symmetry Hamiltonian system phase space.
下载PDF
Ricci Curvature of Certain Submanifolds in Kenmotsu Space Forms
9
作者 Liu JIAN-YU LIu XI-MIN 《Communications in Mathematical Research》 CSCD 2009年第4期340-348,共9页
In this paper, we obtain some sharp inequalities between the Ricci cur- vature and the squared mean curvature for bi-slant and semi-slant submanifolds in Kenmotsu space forms. Estimates of the scalar curvature and the... In this paper, we obtain some sharp inequalities between the Ricci cur- vature and the squared mean curvature for bi-slant and semi-slant submanifolds in Kenmotsu space forms. Estimates of the scalar curvature and the k-Ricci curvature, in terms of the squared mean curvature, are also proved respectively. 展开更多
关键词 Kenmotsu space form Ricci curvature k-Ricci curvature bi-slant sub-manifold semi-slant submanifold
下载PDF
Commuting Structure Jacobi Operator for Real Hypersurfaces in Complex Space Forms
10
作者 U-Hang Ki Hiroyuki Kurihara 《Advances in Pure Mathematics》 2013年第2期264-276,共13页
Let M be a real hypersurface of a complex space form with almost contact metric structure (φ,ξ,η,g). In this paper, we prove that if the structure Jacobi operator Rξ=(·,ξ) ξ is φ▽ξξ-parallel and Rξ com... Let M be a real hypersurface of a complex space form with almost contact metric structure (φ,ξ,η,g). In this paper, we prove that if the structure Jacobi operator Rξ=(·,ξ) ξ is φ▽ξξ-parallel and Rξ commute with the shape operator, then M is a Hopf hypersurface. Further, if Rξ is φ▽ξξ-parallel and Rξ commute with the Ricci tensor, then M is also a Hopf hypersurface provided that TrRξ is constant. 展开更多
关键词 Complex space form Hopf HYPERSURFACE STRUCTURE JACOBI OPERATOR Shape OPERATOR RICCI Tensor
下载PDF
Totally Real Sectional Curvature for Submanifolds in Sasakian Space Forms
11
作者 HUANG Guang-yue MA Bing-qing 《Chinese Quarterly Journal of Mathematics》 CSCD 2011年第2期174-178,共5页
By using the methods introduced by Chen[Chen Bang-yen,A series of Ka¨hlerian invarianrts and their applications to Khlerian geometry,Beitrge Algebra Geom,2001,42(1):165-178],we establish some inequalities for... By using the methods introduced by Chen[Chen Bang-yen,A series of Ka¨hlerian invarianrts and their applications to Khlerian geometry,Beitrge Algebra Geom,2001,42(1):165-178],we establish some inequalities for invariant submanifolds in a Sasakian space form involving totally real sectional curvature and the scalar curvature.Moreover,we consider the case of equalities. 展开更多
关键词 Sasakian space forms invariant submanifolds
下载PDF
RIGIDITY THEOREMS OF COMPLETE K?HLER-EINSTEIN MANIFOLDS AND COMPLEX SPACE FORMS
12
作者 种田 东瑜昕 +1 位作者 林和子 任益斌 《Acta Mathematica Scientia》 SCIE CSCD 2019年第2期339-356,共18页
We concentrate on using the traceless Ricci tensor and the Bochner curvature tensor to study the rigidity problems for complete K?hler manifolds. We derive some elliptic differential inequalities from Weitzenb?ck form... We concentrate on using the traceless Ricci tensor and the Bochner curvature tensor to study the rigidity problems for complete K?hler manifolds. We derive some elliptic differential inequalities from Weitzenb?ck formulas for the traceless Ricci tensor of K?hler manifolds with constant scalar curvature and the Bochner tensor of K?hler-Einstein manifolds respectively. Using elliptic estimates and maximum principle, several L^p and L~∞ pinching results are established to characterize K?hler-Einstein manifolds among K?hler manifolds with constant scalar curvature and complex space forms among K?hler-Einstein manifolds.Our results can be regarded as a complex analogues to the rigidity results for Riemannian manifolds. Moreover, our main results especially establish the rigidity theorems for complete noncompact K?hler manifolds and noncompact K?hler-Einstein manifolds under some pointwise pinching conditions or global integral pinching conditions. To the best of our knowledge,these kinds of results have not been reported. 展开更多
关键词 rigidity theorems Kahler-Einstein complex space forms
下载PDF
ON THE DECOMPOSITION OF COMPLEX VECTOR SPACES AND THE JORDAN CANONICAL FORM OF COMPLEX LINEAR TRANSFORMATIONS
13
作者 肖衡 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1994年第11期997-1003,共7页
New objects characterizing the structure of complex linear transformations areintroduced. These new objects yield a new result for the decomposition of complexvector spaces relative to complex lrnear transformations a... New objects characterizing the structure of complex linear transformations areintroduced. These new objects yield a new result for the decomposition of complexvector spaces relative to complex lrnear transformations and provide all Jordan basesby which the Jordan canonical form is constructed. Accordingly, they can result in thecelebrated Jordan theorem and the third decomposition theorem of space directly. and,moreover, they can give a new deep insight into the exquisite and subtle structure ofthe Jordan form. The latter indicates that the Jordan canonical form of a complexlinear transformation is an invariant structure associated with double arbitrary. choices. 展开更多
关键词 complex vector space complex linear transformation. decompo-sition theorems. Jordan canonical form
下载PDF
Model-Following Designs Using Direct State Derivative Measurement Feedback in Novel Reciprocal State Space Form
14
作者 Yuan-Wei Tseng Rong-Ching Wu 《Journal of Applied Mathematics and Physics》 2019年第2期394-409,共16页
The paper introduces effective and straightforward algorithms of both explicit and implicit model-following designs with state derivative measurement feedback in novel reciprocal state space form (RSS) to handle state... The paper introduces effective and straightforward algorithms of both explicit and implicit model-following designs with state derivative measurement feedback in novel reciprocal state space form (RSS) to handle state derivative related performance output and state related performance output design cases. Applying proposed algorithms, no integrators are required. Consequently, implementation is simple and low-cost. Simulation has also been carried out to verify the proposed algorithms. Since acceleration can only be modeled as state derivative in state space form and micro-accelerometer which is the state derivative sensor is getting more and more attentions in many microelectromechanical and nanoelectromechanical systems (MEMS/NEMS) applications, the proposed algorithms are suitable for MEMS/NEMS systems installed with micro-accelerometers. 展开更多
关键词 Reciprocal STATE space form STATE DERIVATIVE Measurement Feedback EXPLICIT Model-Following DESIGN IMPLICIT Model-Following DESIGN
下载PDF
Chen’s Inequalities for Submanifolds in (<i>&kgreen;, &#181</i>)-Contact Space Form with a Semi-Symmetric Non-Metric Connection
15
作者 Asif Ahmad Faisal Shahzad Jing Li 《Journal of Applied Mathematics and Physics》 2018年第2期389-404,共16页
In this paper, we obtain Chen’s inequalities in (k,?μ)-contact space form with a semi-symmetric non-metric connection. Also we obtain the inequalites for Ricci and K-Ricci curvatures.
关键词 (k µ)-Contact space form Semi-Symmetric Non-Metric CONNECTION Chen’s INEQUALITIES Ricci Curvature
下载PDF
Joint multi-user space time block coding and beamforming via convolutional weighting 被引量:1
16
作者 邢志强 Zhou Tingxian Meng Weixiao 《High Technology Letters》 EI CAS 2006年第2期119-123,共5页
关键词 回旋加权 波束形成 多使用者冲突 中断
下载PDF
<i>L<sup>p</sup>p</i>-Harmonic 1-Forms on <i>δ</i>-Stable Hypersurface in Space Form with Nonnegative Bi-Ricci Curvature
17
作者 Bakry Musa Jiancheng Liu 《Advances in Pure Mathematics》 2021年第5期427-439,共13页
In this paper, we investigate the space of <em>L<sup>p</sup> p</em>-harmonic 1-forms on a complete noncompact orientable <em>δ</em>-stable hypersurface <em>M<sup>m</... In this paper, we investigate the space of <em>L<sup>p</sup> p</em>-harmonic 1-forms on a complete noncompact orientable <em>δ</em>-stable hypersurface <em>M<sup>m</sup></em> that is immersed in space form <img src="Edit_6fbc11b9-ac23-40e2-b045-0fb25419337d.png" width="35" height="23" alt="" /> with nonnegative BiRic curvature. We prove the nonexistence of <em>L<sup>p</sup> p</em>-harmonic 1-forms on <em>M<sup>m</sup></em>. Moreover, we obtain some vanishing properties for this class of harmonic 1-forms. 展开更多
关键词 Lp p-Harmonic 1-forms δ-Stable Hypersurface BiRic Curvature space form
下载PDF
The Form Characteristics and Construction of the Public Space of the Oasis Traditional Settlements in Turpan
18
作者 SAIERJIANG Halike AMANGULI Aishan 《Journal of Landscape Research》 2020年第3期1-4,8,共5页
Based on the analysis of the form characteristics and construction of the public space of oasis traditional settlements in Turpan,and from the analysis and summary of the types,elements,scales and functions of the pub... Based on the analysis of the form characteristics and construction of the public space of oasis traditional settlements in Turpan,and from the analysis and summary of the types,elements,scales and functions of the public space of the traditional settlements,this study put forward that the public space of the oasis villages can be divided into point space,line space and plane space,and the formation and evolution rules of the public space of oasis traditional settlements in Turpan were obtained.Explore the role of public space in the construction of traditional settlements’ overall space,so as to provide reference for the development and renewal of public space of the current similar oasis settlements. 展开更多
关键词 Turpan Oasis settlements Public space form characteristics Construction method
下载PDF
A NON-INCREMENTAL TIME-SPACE ALGORITHM FOR NUMERICAL SIMULATION OF FORMING PROCESS
19
作者 柳葆生 陈大鹏 刘渝 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1996年第11期1021-1029,共9页
A non-incremental time-space algorithm is proposed for numerical. analysis of forming process with the inclusion of geometrical, material, contact-frictional nonlinearities. Unlike the widely used Newton-Raphso... A non-incremental time-space algorithm is proposed for numerical. analysis of forming process with the inclusion of geometrical, material, contact-frictional nonlinearities. Unlike the widely used Newton-Raphson counterpart, the present scheme features an iterative solution procedure on entire time and space domain. Validity and feasibility of foe present scheme are further justiced by the numerical investigation herewith presented. 展开更多
关键词 forming process numerical simulation non-incremental algorithm time-space function
下载PDF
Noether-Form Invariance of Nonholonomic Controllable Mechanical Systems in Phase Space
20
作者 XIA Li-Li LI Yuan-Cheng College of Physics Science and Technology,China University of Petroleum,Dongying 257061,China 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第7期23-26,共4页
In this paper,we study the Noether-form invariance of nonholonomic mechanical controllable systems inphase space.Equations of motion of the controllable mechanical systems in phase space are presented.The definitionan... In this paper,we study the Noether-form invariance of nonholonomic mechanical controllable systems inphase space.Equations of motion of the controllable mechanical systems in phase space are presented.The definitionand the criterion for this system are presented.A new conserved quantity and the Noether conserved quantity deducedfrom the Noether-form invariance are obtained.An example is given to illustrate the application of the results. 展开更多
关键词 nonholonomic controllable mechanical system phase space Noether-form invariance conserved quantity
下载PDF
上一页 1 2 114 下一页 到第
使用帮助 返回顶部