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ON LINEAR EXTENSION OF 1-LIPSCHITZ MAPPING FROM HILBERT SPACE INTO A NORMED SPACE 被引量:2
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作者 王瑞东 《Acta Mathematica Scientia》 SCIE CSCD 2010年第1期161-165,共5页
In this article, we prove that an into 1-Lipschitz mapping from the unit sphere of a Hilbert space to the unit sphere of an arbitrary normed space, which under some conditions, can be extended to be a linear isometry ... In this article, we prove that an into 1-Lipschitz mapping from the unit sphere of a Hilbert space to the unit sphere of an arbitrary normed space, which under some conditions, can be extended to be a linear isometry on the whole space. 展开更多
关键词 Isometric extension Tingley' problem Hilbert space
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One Roper-Suffridge Extension Operator in Complex Banach Spaces 被引量:1
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作者 WANG Xiao-feng XU Yi-fei 《Chinese Quarterly Journal of Mathematics》 CSCD 2013年第3期468-474,共7页
In this paper, by the definition of almost spirallike mappings of type β and order α and the geometric property of the spirallike mapping of type β, we prove that the generalized Roper-Suffridge extension operator ... In this paper, by the definition of almost spirallike mappings of type β and order α and the geometric property of the spirallike mapping of type β, we prove that the generalized Roper-Suffridge extension operator preserves almost spirallikeness of type β and order α in complex Banach spaces. Key words: 展开更多
关键词 Roper-Suffridge extension operator Reinhardt domains complex Banach spaces
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Loewner Chains Associated with the Generalized Roper-Suffridge Extension Operator on the Unit Ball in Hilbert Spaces 被引量:1
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作者 LIU Tao FENG Shu-xia YAN Chun-yan 《Chinese Quarterly Journal of Mathematics》 CSCD 2009年第1期125-131,共7页
In this paper, we prove that the generalized Roper-Suffridge extension operator can be embeded in Loewner chains on the unit ball in Hibert spaces, and obtain the fact that the operator keeps the properties of almost ... In this paper, we prove that the generalized Roper-Suffridge extension operator can be embeded in Loewner chains on the unit ball in Hibert spaces, and obtain the fact that the operator keeps the properties of almost spirallike mapping of typeβ and order α, almost starlikeness of order α, spirallikeness of type ofβ and starlikeness. 展开更多
关键词 Generalized Roper-Suffridge extension oprator Loewner chains Hilbert space almost spirallike mapping of typeβ and order α
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Expanders, Group Extensions, Hadamard Manifolds and Certain Banach Spaces
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作者 SHAN LIN Gong Gui-hua 《Communications in Mathematical Research》 CSCD 2019年第4期335-339,共5页
In this note,we prove that expanders cannot be coarsely embedded into group extensions of sequences of groups which are coarsely embeddable into Hardamad manifolds and certain Banach spaces due to the similar concentr... In this note,we prove that expanders cannot be coarsely embedded into group extensions of sequences of groups which are coarsely embeddable into Hardamad manifolds and certain Banach spaces due to the similar concentration theorems. 展开更多
关键词 EXPANDER group extension HADAMARD MANIFOLD BANACH space
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A Note on Linear Extension of Isometries Between the Unit Spheres in β-normed Spaces
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作者 张子厚 《Northeastern Mathematical Journal》 CSCD 2008年第5期458-464,共7页
In this paper, we give four general results on linear extension of isometries between the unit spheres in β-normed spaces. These results improve the corresponding theorems in β-normed spaces.
关键词 isometric mapping β-normed space extension of isometry Tingley problem
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HARNACK EXTENSION FOR THE HENSTOCK INTEGRAL IN THE EUCLIDEAN SPACE
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作者 Lee Peng Yee(National University of Singapore) 《数学研究》 CSCD 1994年第1期5-8,共4页
HARNACKEXTENSIONFORTHEHENSTOCKINTEGRALINTHEEUCLIDEANSPACE¥LeePengYee(NationalUniversityofSingapore)Abstrat:T... HARNACKEXTENSIONFORTHEHENSTOCKINTEGRALINTHEEUCLIDEANSPACE¥LeePengYee(NationalUniversityofSingapore)Abstrat:TheauthorextendsHa... 展开更多
关键词 亨斯托克积分 哈纳克展开式 欧几里德空间 正函数
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SIR phasing by combination of SOLVE/RESOLVE and dual-space fragment extension involving OASIS
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作者 何尧 古元新 +2 位作者 林政炯 郑朝德 范海福 《Chinese Physics B》 SCIE EI CAS CSCD 2007年第10期3022-3028,共7页
A new phasing procedure has been proposed for dealing with single isomorphous replacement (SIR) x-ray diffraction data. The procedure combines SOLVE/RESOLVE with the dual-space fragment extension involving OASIS. Tw... A new phasing procedure has been proposed for dealing with single isomorphous replacement (SIR) x-ray diffraction data. The procedure combines SOLVE/RESOLVE with the dual-space fragment extension involving OASIS. Two sets of SIR data at 0.28 nm resolution taken from the protein (R)-phycoerythrin (PDB code: 1LIA) were used in the test. For one of the two SIR data sets, a default run of SOLVE/RESOLVE based on the heavy-atom substructure found by SHLEXD led automatically to an interpretable electron density map. OASIS could not effectively improve the result. For the other set of SIR data, SOLVE/RESOLVE resulted in a fragmented model consisting of 454 of the total 668 residues, in which only 29 residues were docked into the sequence. Based on this model, 7 iteration cycles of OASIS-DM- RESOLVE (build only) yielded automatically a model of 547 residues with 133 residues docked into the sequence. The overall-averaged phase error decreased considerably and the quality of electron density map was improved significantly. Two more cycles of iterative OASIS-DM-RESOLVE were carried out, in which the output phases and figures of merit from DM were merged with that from the original run of SOLVE/RESOLVE before they were passed onto RESOLVE (build only). This led automatically to a model containing 452 residues with 173 docked into the sequence. The resultant electron density map is manually traceable. It is concluded that when results of SOLVE/RESOLVE are not sufficiently satisfactory, the combination of SOLVE/RESOLVE and OASIS-DM-RESOLVE (build only) may significantly improve them. 展开更多
关键词 SIR phasing SOLVE/RESOLVE OASIS dual-space fragment extension for proteins
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ON CONDITIONS FOR THE NON LOCALLY CONVEX LINEAR TOPOLOGICAL SPACE TO HAVE THE H.-B. EXTENSION PROPERTY
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作者 SuLinning 《数学研究》 CSCD 1994年第1期158-162,共5页
ONCONDITIONSFORTHENONLOCALLYCONVEXLINEARTOPOLOGICALSPACETOHAVETHEH.-B.EXTENSIONPROPERTY¥SuLinning(Dept.ofMat... ONCONDITIONSFORTHENONLOCALLYCONVEXLINEARTOPOLOGICALSPACETOHAVETHEH.-B.EXTENSIONPROPERTY¥SuLinning(Dept.ofMath.,NingdeTeacher'... 展开更多
关键词 线性拓扑空间 线性连续函数 展开式性质 共轭独立
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A Theorem for Generalized Extension of Operators and Some Applications
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作者 钟怀杰 《Northeastern Mathematical Journal》 CSCD 2001年第4期469-475,共7页
In this note it is shown that every bounded linear operator T∈B(Y, Z) defined on a closed subspace Y of a Banach space X admits a generalized extension T∈B(X, V). Some examples of the applications are given; especia... In this note it is shown that every bounded linear operator T∈B(Y, Z) defined on a closed subspace Y of a Banach space X admits a generalized extension T∈B(X, V). Some examples of the applications are given; especially, a character-ization of H.I. spaces is obtained. 展开更多
关键词 Banach space OPERATOR extension of operator H.I. space
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Harmonic extension of Q-type space related to logarithmic functions
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作者 Jie CUI Pengtao LI 《Frontiers of Mathematics in China》 2024年第5期277-297,共21页
This paper studies a class of Q-type spaces Q^(m)_(log,λ)(R^(n))related to logarithmic functions.We first investigate some basic properties ofQ^(m)_(log,λ)(R^(n)).Further,by the aid of Poisson integral and harmonic ... This paper studies a class of Q-type spaces Q^(m)_(log,λ)(R^(n))related to logarithmic functions.We first investigate some basic properties ofQ^(m)_(log,λ)(R^(n)).Further,by the aid of Poisson integral and harmonic function spaces H^(m)_(log,λ)(R_(+)^(n+1)),the harmonic extension of Q^(m)_(log,λ)(R^(n))and the boundary value problem of H^(m)_(log,λ)(R_(+)^(n+1))are obtained. 展开更多
关键词 Q type space Poisson integral harmonic extension
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ISOMETRY AND PHASE-ISOMETRY OF NON-ARCHIMEDEAN NORMED SPACES
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作者 王瑞东 姚文婷 《Acta Mathematica Scientia》 SCIE CSCD 2023年第6期2377-2386,共10页
In this paper,we study isometries and phase-isometries of non-Archimedean normed spaces.We show that every isometry f:Sr(X)→Sr(X),where X is a finite-dimensional non-Archimedean normed space and Sr(X)is a sphere with... In this paper,we study isometries and phase-isometries of non-Archimedean normed spaces.We show that every isometry f:Sr(X)→Sr(X),where X is a finite-dimensional non-Archimedean normed space and Sr(X)is a sphere with radius r∈||X||,is surjective if and only if is spherically complete and k is finite.Moreover,we prove that if X and Y are non-Archimedean normed spaces over non-trivially non-Archimedean valued fields with|2|=1,any phase-isometry f:X→Y is phase equivalent to an isometric operator. 展开更多
关键词 non-Archimedean normed spaces isometry extension Wigner's theorem
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“In Space” or “As Space”?: Spatial Autocorrelation Properties of the Earth’s Interior
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作者 Charles H. Smith 《International Journal of Geosciences》 2014年第4期375-382,共8页
In this analysis, natural systems are posed to subsystemize in a manner facilitating both structured information/energy sharing and an entropy maximization process projecting a three-dimensional, spatial outcome. Nume... In this analysis, natural systems are posed to subsystemize in a manner facilitating both structured information/energy sharing and an entropy maximization process projecting a three-dimensional, spatial outcome. Numerical simulations were first carried out to determine whether n × n input-output matrices could, once entropy-maximized, project a three-dimensional Euclidean metric. Only 4 × 4 matrices could;a small proportion passed the test. Larger proportions passed when grouped random patterns on and within two- and three-dimensional forms were tested. The pattern of structural zonation within the earth was then tested in analogous fashion using spatial autocorrelation measures, and for three time periods: current, 95 million years b.p. and 200 million years b.p. All expected results were obtained;not only do the geometries of zonation project a three-dimensional structure as anticipated, but also do secondary statistical measures reveal levels of equilibrium among the zones in all three cases that are nearly total, distinguishing them from simulations that do not incorporate a varying-surface zone-width element. 展开更多
关键词 Entropy Maximization Earth’s INTERIOR SPATIAL AUTOCORRELATION BENEDICT de SPINOZA SPATIAL extension space
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A Simple Proof for a Property of the Vector Space Ⅴ Over the Field F
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作者 Li Heng—pei(Depurtnent of Applied Mathematics and Physics Beyjing University of Aeronantics and Astronautics) 《大学数学》 1993年第1期8-10,共3页
In this paper we’ll prove a fundameutal property of the vector space by means of the ex-tension field,i.e.the numbers of the elements of a basis of the vector space V over the field Fequal to the d imensions(V:F).
关键词 FIELD extension FIELD VECTOR space dimecsion BASIS
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Think " Big" and become " Big" : On the architectureand space of an urban museum
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作者 ZHAO Wenjun 《科学教育与博物馆》 2016年第3期223-229,共7页
Nowadays many urban museums are situated in ever-changing cities face with problems regardingspace and architecture. The main question this paper wants to discuss is how the museum could achieve accessibilityand inclu... Nowadays many urban museums are situated in ever-changing cities face with problems regardingspace and architecture. The main question this paper wants to discuss is how the museum could achieve accessibilityand inclusiveness to a greater extent via rethinking and reshaping its space, both physically and vir -tually,Based on practices conducted by the Museum of London since its establishment in the 20th century, Iendeavour to understand how the museum architecture was established during the negotiation and compro -mise among different individuals and parties and to extend the conception by exploring the possibilities of expanding out of the traditional realm of the museum architecture. 展开更多
关键词 museum architecture space extension
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Extension of isometries on the unit sphere of l^p (Γ) space 被引量:10
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作者 FANG XiNian 1,& WANG JianHua 2 1 School of Mathematics and Statistics,Nanjing Audit University,Nanjing 210029,China 2 Department of Mathematics,Anhui Normal University,Wuhu 241000,China 《Science China Mathematics》 SCIE 2010年第4期1085-1096,共12页
In this paper,we obtain that every isometry from the unit sphere S(l p (Γ)) of l p (Γ) (1 【 p 【 ∞,p≠2) onto the unit sphere S(E) of a Banach space E can be extended to be a (real) linear isometry of l p (Γ) ont... In this paper,we obtain that every isometry from the unit sphere S(l p (Γ)) of l p (Γ) (1 【 p 【 ∞,p≠2) onto the unit sphere S(E) of a Banach space E can be extended to be a (real) linear isometry of l p (Γ) onto E,so,we give an affirmative answer to the corresponding Tingley’s problem. 展开更多
关键词 ISOMETRIC extension l P (Γ) space ISOMETRY 1-Lipschitz mapping
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Polynomials,Higher Order Sobolev Extension Theorems and Interpolation Inequalities on Weighted Folland-Stein Spaces on Stratified Groups 被引量:10
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作者 Guozhen Lu Department of Mathematics,Wayne State University,Detroit,MI 48202,USA 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2000年第3期405-444,共40页
This paper consists of three main parts.One of them is to develop local and global Sobolev interpolation inequalities of any higher order for the nonisotropic Sobolev spaces on stratified nilpotent Lie groups.Despite ... This paper consists of three main parts.One of them is to develop local and global Sobolev interpolation inequalities of any higher order for the nonisotropic Sobolev spaces on stratified nilpotent Lie groups.Despite the extensive research after Jerison’s work[3]on Poincaré-type inequalities for Hrmander’s vector fields over the years,our results given here even in the nonweighted case appear to be new.Such interpolation inequalities have crucial applications to subelliptic or parabolic PDE’s involving vector fields.The main tools to prove such inequalities are approximating the Sobolev func- tions by polynomials associated with the left invariant vector fields on G.Some very useful properties for polynomials associated with the functions are given here and they appear to have independent interests in their own rights.Finding the existence of such polynomials is the second main part of this paper.Main results of these two parts have been announced in the author’s paper in Mathematical Research Letters[38]. The third main part of this paper contains extension theorems on anisotropic Sobolev spaces on stratified groups and their applications to proving Sobolev interpolation inequalities on(εδ)domains. Some results of weighted Sobolev spaces are also given here.We construct a linear extension operator which is bounded on different Sobolev spaces simultaneously.In particular,we are able to construct a bounded linear extension operator such that the derivatives of the extended function can be controlled by the same order of derivatives of the given Sobolev functions.Theorems are stated and proved for weighted anisotropic Sobolev spaces on stratified groups. 展开更多
关键词 Poincaré inequalities extension theorems Interpolation inequalities Anisotropic Sobolev spaces A_p weights δ)domains Vector fields Polynomials on stratified groups
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Leakage Is Prohibited:Memory Protection Extensions Protected Address Space Randomization 被引量:2
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作者 Fei Yan Kai Wang 《Tsinghua Science and Technology》 SCIE EI CAS CSCD 2019年第5期546-556,共11页
Code reuse attacks pose a severe threat to modern applications. These attacks reuse existing code segments of vulnerable applications as attack payloads and hijack the control flow of a victim application. With high c... Code reuse attacks pose a severe threat to modern applications. These attacks reuse existing code segments of vulnerable applications as attack payloads and hijack the control flow of a victim application. With high code entropy and a relatively low performance overhead, Address Space Layout Randomization(ASLR) has become the most widely explored defense against code reuse attacks. However, a single memory disclosure vulnerability is able to compromise this defense. In this paper, we present Memory Protection Extensions(MPX)-assisted Address Space Layout Randomization(M-ASLR), a novel code-space randomization scheme. M-ASLR uses several characteristics of Intel MPX to restrict code pointers in memory. We have developed a fully functioning prototype of M-ALSR, and our evaluation results show that M-ASLR:(1) offers no interference with normal operation;(2) protects against buffer overflow attacks, code reuse attacks, and other sophisticated modern attacks;and(3) adds a very low performance overhead(3.3%) to C/C++ applications. 展开更多
关键词 ADDRESS space Layout RANDOMIZATION (ASLR) Intel Memory Protection extensionS (MPX) code REUSE attack
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射孔间距-倾角对深煤层水力裂缝扩展影响的离散元分析
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作者 安果涛 谢昕 +1 位作者 孔祥伟 王存武 《科学技术与工程》 北大核心 2024年第18期7623-7629,共7页
研究煤岩储层裂缝扩展的影响因素,对提高煤层气采收率十分重要。为探究不同射孔间距-倾角对深层煤岩裂缝扩展规律的影响,利用离散元分析方法,考虑井周煤岩应力变化特征、最大周向应力准则、原始储层等条件,研究射孔间距-倾角对压裂缝网... 研究煤岩储层裂缝扩展的影响因素,对提高煤层气采收率十分重要。为探究不同射孔间距-倾角对深层煤岩裂缝扩展规律的影响,利用离散元分析方法,考虑井周煤岩应力变化特征、最大周向应力准则、原始储层等条件,研究射孔间距-倾角对压裂缝网扩展形态及延伸范围的影响规律。模拟结果表明:随射孔间距从40 mm变化至100 mm,当间距为60 mm时裂缝条数数量最多;当射孔倾角从15°到60°变化时,当射孔角度为45°时,缝网形态最为复杂;即射孔间距为60 mm且射孔倾角为θ=45°时,水力裂缝的缝网形态复杂度显著增大,缝网扩展范围最大。通过神府北木瓜区Y-1井验证,预测结果与实测数据具有一致性,证明所建煤岩数值模型的正确性。 展开更多
关键词 深煤岩 射孔间距-倾角 离散元 水力裂缝扩展 煤岩应力
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The isometrical extensions of 1-Lipschitz mappings on Gteaux differentiability spaces 被引量:2
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作者 DING GuangGui 《Science China Mathematics》 SCIE 2011年第4期711-722,共12页
Let X and Y be real Banach spaces.Suppose that the subset sm[S1(X)] of the smooth points of the unit sphere [S1(X)] is dense in S1(X).If T0 is a surjective 1-Lipschitz mapping between two unit spheres,then,under some ... Let X and Y be real Banach spaces.Suppose that the subset sm[S1(X)] of the smooth points of the unit sphere [S1(X)] is dense in S1(X).If T0 is a surjective 1-Lipschitz mapping between two unit spheres,then,under some condition,T0 can be extended to a linear isometry on the whole space. 展开更多
关键词 1-Lipschitz mapping linearly isometric extension Ga teaux differentiability space smooth point
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The isometric extension of “into” mappings on unit spheres of AL-spaces 被引量:7
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作者 DING GuangGui School of Mathematics Science, Chern Institute of Mathematics and LPMC, Nankai University, Tianjin 300071, China 《Science China Mathematics》 SCIE 2008年第10期1904-1918,共15页
In this paper, we show that if V0 is an isometric mapping from the unit sphere of an AL-space onto the unit sphere of a Banach space E, then V0 can be extended to a linear isometry defined on the whole space.
关键词 ISOMETRIC extension (atomic) AL-space
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