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The generators of Lorentz transformation in momentum space

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Science China Mathematics 2002年第2期45卷 241-245页

作者：张鹏飞阮图南 CCAST (World Lab.) P. O. Box 8730 Beijing 100080 China Natl. Synchrt. Radiation Laboratory Department of Modern Physics Univ. of Sci. and Technol. of China Hefei 230029 China

In the momentum space, the angular momentum operator and the boost vector operator,i.e. the generators for the Lorentz transformation of a particle with arbitrary spin and nonzero mass are discussed. Some new expressi... 详细信息

关键词： momentum space, angular momentum operator, boost vector operator.

Think ＂ Big＂ and become ＂ Big＂： On the architectureand space of an urban museum

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科学教育与博物馆 2016年第3期2卷 223-229页

作者： ZHAO Wenjun Shanghai Natural History Museum (巳ranch of Shanghai Science & Technology Museum)

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.

关键词： museum, architecture, space, extension

The endemic Patagonian vespertilionid assemblage is a depauperate ecomorphological vicariant of species-rich neotropical assemblages

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Current Zoology 2017年第5期63卷 495-505页

作者： Analia L. GIMENEZ Norberto P, GIANNINI Centro de Investigacion Esquel de Montafia y Estepa Patagonicas (CIEMEP CONICET-UNPSJB) Laboratorio de Investigaciones en Evoluci6n y Biodiversidad (LIEB) Roca 780 Esquel Chubut CP 9200 Argentina Unidad Ejecutora Lillo Consejo Nacional de Investigaciones Cientfficas y Tecnicas (CONICET) Fundacion Miguel Lillo Facultad de Ciencias Naturales e Instituto Miguel Lillo Universidad Nacional de Tucuman San Miguel de Tucuman Tucuman Argentina

Vespertilionidae is the most diverse chiropteran family, and its diversity is concentrated in warmregions of the World; however, due to physiological and behavioral adaptations, these bats alsodominate bat faunas in temperate regions. Here we performed a comparative study of vespertili-onid assemblages from two broad regions of the New World, the cold and harsh Patagonia, versusthe remaining temperate-to-subtropical, extra-Patagonian eco-regions of the South AmericanSouthern Cone. We took an ecomorphological approach and analyzed the craniodental morpho-logical structure of these assemblages within a phylogenetic framework. We measured 17 cranio-dental linear variables from 447 specimens of 22 currently recognized vespertilionid species of thestudy regions. We performed a multivariate analysis to define the morphofunctional space, andcalculated the pattern and degree of species packing for each assemblage. We assessed the im-portance of phylogeny and biogeography, and their impact on depauperate （Patagonian） versusrich （extra-Patagonian） vespertilionid assemblages as determinants of morphospace structuring.We implemented a sensitivity analysis associated to small samples of rare species. The morpho-logical patterns were determined chiefly by the evolutionary history of the family. The Patagonianassemblage can be described as a structurally similar but comparatively depauperate ecomorpho-logical version of those assemblages from neighboring extra-Patagonian eco-regions. ThePatagonian assemblage seems to have formed by successively adding populations from Northernregions that eventually speciated in the region, leaving corresponding sisters （vicariants） in extra-Patagonian eco-regions that continued to be characteristically richer. Despite being structurallyakin, degree of species packing in Patagonia was comparatively very low, which may reflect the ef-fect of limited dispersal success into a harsh region for bat survival.

关键词： Vespertilionidae, Patagonia, morphological space, biogeography, phylogeny.

Toeplitz operators related to strongly singular Calderón-Zygmund operators

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Science China Mathematics 2006年第8期49卷 1048-1064页

作者： LIN Yan LU Shanzhen School of Mathematical Sciences Beijing Normal University Beijing 100875 China School of Mathematical Sciences Beijing Normal University Beijing 100875 China

In this paper, the boundedness of Toeplitz operator Tb(f) related to strongly singular Calderón-Zygmund operators and Lipschitz function b ∈(Λ)β0(Rn) is discussed from Lp(Rn) to Lq(Rn),1/q=1/p-β0/n, and from Lp(Rn) to Triebel-Lizorkin space (F)β0,∞p. We also obtain the boundedness of generalized Toeplitz operator Θbα0 from Lp(Rn) to Lq(Rn), 1/q=1/p-α0+β0/n.All the above results include the corresponding boundedness of commutators. Moreover, the boundedness of Toeplitz operator Tb(f) related to strongly singular Calderón-Zygmund operators and BMO function b is discussed on Lp(Rn), 1 ＜ p ＜ ∞ .

关键词： Toeplitz operator, strongly singular Calderón-Zygmund operator, Lipschitz space, Triebel-Lizorkin space, BMO.

Bloch spaces on bounded symmetric domains in complex Banach spaces

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Science China Mathematics 2006年第11期49卷 1625-1632页

作者： DENG Fangwen OUYANG Caiheng Wuhan Institute of Physics and Mathematics Chinese Academy of Sciences Wuhan 430071 China Wuhan Institute of Physics and Mathematics Chinese Academy of Sciences Wuhan 430071 China

We give a definition of Bloch space on bounded symmetric domains in arbitrary complex Banach space and prove such function space is a Banach space. The properties such as boundedness, compactness and closed range of c... 详细信息

关键词： Bloch space, bounded symmetric domain, composition operator.

Composition operators between Bloch-type spaces in the polydisc

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Science China Mathematics 2005年第Z1期48卷 268-282页

作者： HU Zhangjian Huzhou Teachers College Huzhou313000China

We characterize those holomorphic mappings ψ from the polydisc Dn in Cn to itself for which the induced composition operators Cψ are bounded (or compact) from the Bloch-type space Bω to βμ (respectively, from the little Bloch-type space Bω,0 to Bμ,0),where ω is a normal function on [0, 1) andμ is a nonnegative function on [0, 1) withμ(tn) ＞ 0for some sequence {tn}n∞n=1(∪) [0, 1) satisfying limn→∞ tn = 1.

关键词： Bloch-type space, composition operator, boundedness, compactness.

Convergence rate of Gibbs sampler and its application

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Science China Mathematics 2005年第10期48卷 1430-1439页

作者： LI Kaican GENG Zhi Department of Mathematics Hubei Normal University Huangshi 435002 China LMAM School of Mathematical Sciences Peking University Beijing 100871 China LMAM School of Mathematical Sciences Peking University Beijing 100871 China

Based on the convergence rate defined by the Pearson-x2 distance, this paper discusses properties of different Gibbs sampling schemes. Under a set of regularity conditions, it is proved in this paper that the rate of convergence on systematic scan Gibbs samplers is the norm of a forward operator. We also discuss that the collapsed Gibbs sampler has a faster convergence rate than the systematic scan Gibbs sampler as proposed by Liu et al. Based on the definition of convergence rate of the Pearson-x2 distance,this paper proved this result quantitatively. According to Theorem 2, we also proved that the convergence rate defined with the spectral radius of matrix by Robert and Shau is equivalent to the corresponding radius of the forward operator.

关键词： compact operator, Gibbs samplers, Hilbert space, transition function.

Hankel and Toeplitz type operators on the unit disk

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Science China Mathematics 2002年第9期45卷 1154-1162页

作者：何建勋彭立中 Sch. of Math. and Computer Science Nanjing Normal University Nanjing 210097 China School of Mathematical Science Peking University Beijing 100871 China

Let D be the unit disk in the complex plane with the weighted measure dμβ(z) = (β+1)--π(1-|z|2)βdm(z)(β＞-1). Then L2(D,dμβ(z)) = ∞k=0(Aβk Aβk) is the orthogonal direct sum decomposition.In this paper, we define the Hankel and Toeplitz type operators, and study the boundedness, compactness and Sp-criteria for them.

关键词： Hankel type operator, Toeplitz type operator, Sp-criteria, analytic Besov space, para-commutator.

Boundedness from below of composition operators on the Bloch spaces

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Science China Mathematics 2003年第6期46卷 838-846页

作者：陈怀惠 Department of Mathematics Nanjing Normal University Nanjing 210097 China

This paper proves that a necessary condition for a composition operator on the Bloch space of the unit disk to be bounded below given by Ghatage, Yah and Zheng is also sufficient. Given furthermore are a sufficient condition and a necessary condition of the boundedness from below for a composition operator on the Bloch space of a unit ball with dimensions bigger than one.

关键词： Bloch space, composition operator, boundedness from below.