中国科学院数学与系统科学研究院期刊网

15 December 2014, Volume 30 Issue 12
    

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  • Chang Yu GUO
    Acta Mathematica Sinica. 2014, 30(12): 1999-2013. https://doi.org/10.1007/s10114-014-3619-0
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    Let f: Ω → f(Ω) ⊂ Rn be a W1,1-homeomorphism with L1-integrable inner distortion.We show that finiteness of min{lipf(x), kf(x)}, for every x ∈ Ω\E, implies that f-1W1,n and has finite distortion, provided that the exceptional set E has σ-finite H1-measure. Moreover, f has finite distortion, differentiable a.e. and the Jacobian Jf > 0 a.e.
  • Xue Xiu ZHONG, Wen Ming ZOU
    Acta Mathematica Sinica. 2014, 30(12): 2014-2026. https://doi.org/10.1007/s10114-014-3509-5
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    Consider the Schrödinger system

    where Ω ⊂ RN, α,β > 1, α +β < 2* and the spectrum σ(-Δ+Vi,n) ⊂ (0,+∞), em = 1, 2; Qn is a bounded function and is positive in a region contained in Ω and negative outside. Moreover, the sets {Qn > 0} shrink to a point x0 ∈ Ω as n→ +∞. We obtain the concentration phenomenon. Precisely, we first show that the system has a nontrivial solution (un, vn) corresponding to Qn, then we prove that the sequences (un) and (vn) concentrate at x0 with respect to the H1-norm. Moreover, if the sets {Qn> 0} shrink to finite points and (un, vn) is a ground state solution, then we must have that both un and vn concentrate at exactly one of these points. Surprisingly, the concentration of un and vn occurs at the same point. Hence, we generalize the results due to Ackermann and Szulkin [Arch. Rational Mech. Anal., 207, 1075-1089 (2013)].
  • Rong ZHU, Guo Hua ZOU
    Acta Mathematica Sinica. 2014, 30(12): 2027-2044. https://doi.org/10.1007/s10114-014-2707-5
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    The linear mixed-effects model (LMM) is a very useful tool for analyzing cluster data. In practice, however, the exact values of the variables are often difficult to observe. In this paper, we consider the LMM with measurement errors in the covariates. The empirical BLUP estimator of the linear combination of the fixed and random effects and its approximate conditional MSE are derived. The application to the estimation of small area is provided. Simulation study shows good performance of the proposed estimators.
  • Xin ZHANG
    Acta Mathematica Sinica. 2014, 30(12): 2045-2053. https://doi.org/10.1007/s10114-014-3763-6
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    A graph is 1-planar if it can be drawn on a plane so that each edge is crossed by at most one other edge. A plane graph with near independent crossings (say NIC-planar graph) is a 1-planar graph with the restriction that for any two crossings the four crossed edges are incident with at most one common vertex. The full characterization of NIC-planar complete and complete multipartite graphs is given in this paper.
  • Yue Zhu WU, Xiao Qing YUE, Lin Sheng ZHU
    Acta Mathematica Sinica. 2014, 30(12): 2054-2062. https://doi.org/10.1007/s10114-014-3743-x
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    We explicitly compute the first and second cohomology groups of the Schrödinger algebra S(1) with coefficients in the trivial module and the finite-dimensional irreducible modules. We also show that the first and second cohomology groups of S(1) with coefficients in the universal enveloping algebras U(S(1)) (under the adjoint action) are infinite dimensional.
  • Li LIANG, Nan Qing DING, Gang YANG
    Acta Mathematica Sinica. 2014, 30(12): 2063-2078. https://doi.org/10.1007/s10114-014-3227-z
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    In this paper, we give a relationship between projective generators (resp., injective cogenerators) in the category of R-modules and the counterparts in the category of complexes of R-modules. As a consequence, we get that complexes of W-Gorenstein modules are actually -Gorenstein complexes whenever W is a subcategory of R-modules satisfying WW, where  is the subcategory of exact complexes with all cycles in W. We also study when all cycles of a -Gorenstein complexes are W-Gorenstein modules.
  • Huai Liang CHANG
    Acta Mathematica Sinica. 2014, 30(12): 2079-2084. https://doi.org/10.1007/s10114-014-2730-6
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    Let S be a smooth algebraic surface and let L be a line bundle on S. Suppose there is a holomorphic two form over S with zero loci to be a curve C. We show that the Donaldson-Thomas invariant of the P1 scroll X= P(LOS) vanishes unless the curves being enumerated lie in D= P(L|COC). Our method is cosection localization of Y.-H. Kiem and J. Li.
  • Hong Chang HU, Lei SONG
    Acta Mathematica Sinica. 2014, 30(12): 2085-2102. https://doi.org/10.1007/s10114-014-1410-x
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    The paper studies a generalized linear model (GLM)
    yt=h(xtTβ) + εt, t= 1, 2,...,n,
    where
    ε1=η1, εt=ρεt-1+ηt,t= 2, 3,..., n,
    h is a continuous differentiable function, ηt's are independent and identically distributed random errors with zero mean and finite variance σ2. Firstly, the quasi-maximum likelihood (QML) estimators of β, ρ and σ2 are given. Secondly, under mild conditions, the asymptotic properties (including the existence, weak consistency and asymptotic distribution) of the QML estimators are investigated. Lastly, the validity of method is illuminated by a simulation example.
  • Evren ERGÜN, Ergin BAYRAM, Emin KASAP
    Acta Mathematica Sinica. 2014, 30(12): 2103-2118. https://doi.org/10.1007/s10114-014-1502-7
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    In this paper, we analyze the problem of constructing a surface pencil from a given spacelike (timelike) line of curvature. Using the Frenet frame of the given line of curvature in Minkowski 3-space, we express the surface pencil as a linear combination of this frame and derive the necessary and sufficient conditions for the coefficients to satisfy the line of curvature requirement. We illustrate this method by presenting some examples.
  • Ti Ren HUANG, Xiao Ping YANG
    Acta Mathematica Sinica. 2014, 30(12): 2119-2136. https://doi.org/10.1007/s10114-014-1286-9
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    Let G be a connected Lie group and D be a bracket generating left invariant distribution. In this paper, first, we prove that all sub-Riemannian minimizers are smooth in Lie groups if the distribution D satisfies [D, [D,D]] ⊂ D and [K, [K,K]] ⊂ K for any proper sub-distribution K of D. Second, we prove that all sub-Riemannian minimizers are smooth in Lie group if the rank-3 distribution D satisfies Condition (B). Third, we discuss characterizations of normal extremals, abnormal extremals, rigid curves, and minimizers on product sub-riemannian Lie groups. We prove that not all strictly abnormal minimizers are rigid curves and construct a strictly abnormal minimizer which is not a rigid curve.
  • Xiao Min DUAN, Hua Fei SUN, Lin Yu PENG
    Acta Mathematica Sinica. 2014, 30(12): 2137-2145. https://doi.org/10.1007/s10114-014-1285-x
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    Geometric structures of a manifold of positive definite Hermite matrices are considered from the viewpoint of information geometry. A Riemannian metric is defined and dual α-connections are introduced. Then the fact that the manifold is ±1-flat is shown. Moreover, the divergence of two points on the manifold is given through dual potential functions. Furthermore, the optimal approximation of a point onto the submanifold is gotten. Finally, some simulations are given to illustrate our results.
  • Xing Xiao LI, Tian Qun ZHANG
    Acta Mathematica Sinica. 2014, 30(12): 2146-2160. https://doi.org/10.1007/s10114-014-1184-1
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    In this paper, we obtain a sufficient and necessary condition for a simply connected Riemannian manifold (Mn, g) to be isometrically immersed, as a submanifold with codimension p ≥ 1, into the product Sk×Hn+p-k of sphere and hyperboloid.
  • Hua Ming WANG
    Acta Mathematica Sinica. 2014, 30(12): 2161-2172. https://doi.org/10.1007/s10114-014-3650-1
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    In this paper, we form a method to calculate the probability generating function of the total progeny of multitype branching process. As examples, we calculate probability generating function of the total progeny of the multitype branching processes within random walk which could stay at its position and (2-1) random walk. Consequently, we could give the probability generating functions and the distributions of the first passage time of corresponding random walks. Especially, for recurrent random walk which could stay at its position with probability 0 < r < 1, we show that the tail probability of the first passage time decays as  when n→∞.