中国科学院数学与系统科学研究院期刊网

15 August 2005, Volume 21 Issue 4
    

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  • Li Ning JIANG, Mao Zheng GUO
    Acta Mathematica Sinica. 2005, 21(4): 673-680. https://doi.org/10.1007/s10114-004-0513-1
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    Suppose that G is a finite group and D(G) the double algebra of G. For a given subgroup H of G, there is a sub-Hopf algebra D(G;H) of D(G). This paper gives the concrete construction of a D(G;H)-invariant subspace H in field algebra of G-spin model and proves that if H is a normal subgroup of G, then AH is Galois closed.
  • Ajda FOŠNER, PeterŠEMRL
    Acta Mathematica Sinica. 2005, 21(4): 681-684. https://doi.org/10.1007/s10114-005-0519-3
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    We characterize the additive singularity preserving almost surjective maps on Mn (F), the algebra of all n × n matrices over a field F with char F = 0. We also describe additive invertibility preserving surjective maps on Mn (F) and give examples showing that all the assumptions in these two theorems are indispensable.
  • Shi Xia LUAN, An Min MAO
    Acta Mathematica Sinica. 2005, 21(4): 685-690. https://doi.org/10.1007/s10114-005-0532-6
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    In this paper, we develop the local linking theorem given by Li and Willem by replacing the Palais-Smale condition with a Cerami one, and apply it to the study of the existence of periodic solutions of the nonautonomous second order Hamiltonian systems
    Aü + A(t) u + ∇V (t, u) = 0, u ∈ RN, t ∈ R.
    We handle the case of superquadratic nonlinearities which differ from those used previously. Our results extend the theorems given by Li and Willem.
  • Qing Liu YAO
    Acta Mathematica Sinica. 2005, 21(4): 691-698. https://doi.org/10.1007/s10114-004-0401-8
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    The existence, multiplicity and infinite solvability of positive solutions are established for some two-point boundary value problems of one-dimensional p-Laplacian. In this paper, by multiplicity we mean the existence of m solutions, where m is an arbitrary natural number.
  • Hui Li YAO, Ting Fu WANG
    Acta Mathematica Sinica. 2005, 21(4): 699-704. https://doi.org/10.1007/s10114-004-0429-9
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    In this paper, we give the formula of Maluta's coefficient for calculation, and don't add any conditions to the generating function Φ.
  • Qi Kang RAN
    Acta Mathematica Sinica. 2005, 21(4): 705-714. https://doi.org/10.1007/s10114-005-0569-6
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    In this paper, we prove that the weak solutions of the following equation with vanishing mean oscillation coefficients A(x): belong to , provided and B(x, u, h) satisfies proper growth conditions, where Ω ⊂ RN (N ≥ 2) is a bounded open set, A(x) = (Aij (x))N×N is a symmetric matrix function.
  • Yun Yan YANG, Xiao Xiang JIAO
    Acta Mathematica Sinica. 2005, 21(4): 715-722. https://doi.org/10.1007/s10114-004-0426-z
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    In this paper, curve shortening flow in Euclidian space Rn (n ≥ 3) is studied, and S. Altschuler's results about flow for space curves are generalized. We prove that the curve shortening flow converges to a straight line in infinite time if the initial curve is a ramp. We also prove the planar phenomenon when the curve shortening flow blows up.
  • Mao Fa WANG, Pei De LIU
    Acta Mathematica Sinica. 2005, 21(4): 723-732. https://doi.org/10.1007/s10114-004-0441-0
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    In this paper, we study the compactness of the product of a composition operator with another one's adjoint on the Bergman space. Some necessary and sufficient conditions for such operators to be compact are given.
  • E. M. E. ZAYED
    Acta Mathematica Sinica. 2005, 21(4): 733-752. https://doi.org/10.1007/s10114-004-0514-0
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    The trace of the wave kernel are the eigenvalues of the negative Laplacian in the (x1, x2, x3)-space, is studied for a variety of bounded domains, where -∞ < t < ∞ and . The dependence of û(t) on the connectivity of bounded domains and the Dirichlet, Neumann and Robin boundary conditions are analyzed. Particular attention is given for a multi-connected vibrating membrane Ω in R3 surrounded by simply connected bounded domains Ωj with smooth bounding surfaces Sj (j = 1, . . ., n), where a finite number of piecewise smooth Dirichlet, Neumann and Robin boundary conditions on the piecewise smooth components (i = 1+kj-1 , . . ., kj ) of the bounding surfaces S j are considered, such that , where k0 = 0. The basic problem is to extract information on the geometry Ω by using the wave equation approach from a complete knowledge of its eigenvalues. Some geometrical quantities of Ω (e.g. the volume, the surface area, the mean curvuture and the Gaussian curvature) are determined from the asymptotic expansion of û (t) for small |t|.
  • Zong Xuan CHEN, Kwang Ho SHON
    Acta Mathematica Sinica. 2005, 21(4): 753-764. https://doi.org/10.1007/s10114-004-0434-z
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    In this paper, we investigate the growth and fixed points of solutions and their 1st, 2nd derivatives, differential polynomial of second order linear differential equations with meromorphic coefficients, and obtain that the exponents of convergence of these fixed points are all equal to the order of growth.
  • Pu ZHANG, Jie Cheng CHEN
    Acta Mathematica Sinica. 2005, 21(4): 765-772. https://doi.org/10.1007/s10114-004-0457-5
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    In this paper, we study the commutator generalized by a multiplier and a Lipschitz function. Under some assumptions, we establish the boundedness properties of it from Lp (Rn ) into (Rn ), the Triebel-Lizorkin spaces.
  • Yan WANG, Rong Quan FENG
    Acta Mathematica Sinica. 2005, 21(4): 773-778. https://doi.org/10.1007/s10114-004-0455-7
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    A Cayley map is a Cayley graph embedded in an orientable surface such that the local rotations at every vertex are identical. In this paper, balanced regular Cayley maps for cyclic groups, dihedral groups, and generalized quaternion groups are classified.
  • Gerold ALSMEYER, Markus JAEGER
    Acta Mathematica Sinica. 2005, 21(4): 779-786. https://doi.org/10.1007/s10114-004-0524-y
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    Given a continuous semimartingale M = (Mt)t≥0 and a d-dimensional continuous process of locally bounded variation V = (V1, . . ., Vd), the multidimensional Itô Formula states that
    if f(x0, . . ., xd) is of C2-type with respect to x0 and of C1-type with respect to the other arguments. This formula is very useful when solving various optimal stopping problems based on Brownian motion. However, in such application the function f typically fails to satisfy the stated conditions in that its first partial derivative with respect to x0 is only absolutely continuous. We prove that the formula remains true for such functions and demonstrate its use with two examples from Mathematical Finance.
  • Cai Shi WANG, Zhi Yuan HUANG, Xiang Jun WANG
    Acta Mathematica Sinica. 2005, 21(4): 787-796. https://doi.org/10.1007/s10114-004-0456-6
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    In this paper we first introduce and investigate some special classes of nonlinear maps and get several useful results. Then, by using these results, we obtain analytic criteria for checking whether or not an operator defined only on the exponential vectors of a symmetric Fock space becomes a Hilbert-Schmidt operator on the whole space. Additionally, as an application, we also get an analytic criterion for Hilbert-Schmidt operators on a Gaussian probability space through the Wiener-Itô-Segal isomorphism.
  • Shi Rong LI
    Acta Mathematica Sinica. 2005, 21(4): 797-802. https://doi.org/10.1007/s10114-004-0357-8
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    For a finite group G, let τ(G) denote a set of primes such that a prime p belongs to τ(G) if and only if p is a divisor of the index of some maximal subgroup of G. It is proved that if G satisfies any one of the following conditions: (1) G has a p-complement for each p∈τ(G); (2) |τ(G)|=2; (3) the normalizer of a Sylow p-subgroup of G has prime power index for each odd prime p∈τ(G); then G either is solvable or G/Sol(G) (2, 7) where Sol(G) is the largest solvable normal subgroup of (G).
  • Der Chen CHANG, Jing Zhi TIE
    Acta Mathematica Sinica. 2005, 21(4): 803-818. https://doi.org/10.1007/s10114-004-0336-0
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    In this note, we compute the fundamental solution for the Hermite operator with singularity at an arbitrary point y∈Rn . We also apply this result to obtain the fundamental solutions for the Grushin operator in R2 and the sub-Laplacian in the Heisenberg group Hn .
  • Xi Cheng ZHANG
    Acta Mathematica Sinica. 2005, 21(4): 819-822. https://doi.org/10.1007/s10114-005-0529-1
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    In this note, we obtain a sufficient and necessary condition for a set in an abstract Wiener space (X, H, μ) to be relatively compact in L2(X, μ). Meanwhile, we give a sufficient condition for relative compactness in Lp (X, μ) for p > 1. We also provide an example of Da Prato-Malliavin-Nualart to show the result.
  • Feng WEI
    Acta Mathematica Sinica. 2005, 21(4): 823-832. https://doi.org/10.1007/s10114-005-0563-z
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    Let R be a semiprime ring with characteristic p ≥ 0 and RF be its left Martindale quotient ring. If is a reduced generalized differential identity for an essential ideal of R, then Φ(Zij ej )) is a generalized polynomial identity for RF , where ej ) are idempotents in the extended centroid of R determined by Δj . Let R be a prime ring and Q be its symmetric Martindale quotient ring. If is a reduced generalized differential identity for a noncommutative Lie ideal of R, then Φ(Zij ) is a generalized polynomial identity for[R,R]. Moreover, if is a reduced generalized differential identity, with coefficients in Q, for a large right ideal of R, then Φ(Zij ) is a generalized polynomial identity for Q.
  • Claus BAUER
    Acta Mathematica Sinica. 2005, 21(4): 833-840. https://doi.org/10.1007/s10114-004-0506-0
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    Let Pi , 1 ≤ i ≤ 5, be prime numbers. It is proved that every integer N that satisfies N ≡ 5(mod24) can be written as .
  • Tae Wan KIM, Hong Kyung PAK
    Acta Mathematica Sinica. 2005, 21(4): 841-846. https://doi.org/10.1007/s10114-004-0520-2
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    The purpose of this paper is to study the canonical foliations of an almost cosymplectic or almost Kenmotsu manifold M in a unified way. We prove that the canonical foliation F defined by the contact distribution is Riemannian and tangentially almost Köhler of codimension 1 and that F is tangentially K?hler if the manifold M is normal. Furthermore, we show that a semi-invariant submanifold N of such a manifold M admits a canonical foliation FN which is defined by the antiinvariant distribution and a canonical cohomology class c(N) generated by a transversal volume form for FN . In addition, we investigate the conditions when the even-dimensional cohomology classes of N are non-trivial. Finally, we compute the Godbillon-Vey class for FN .
  • Mao Hua LE
    Acta Mathematica Sinica. 2005, 21(4): 843-848. https://doi.org/10.1007/s10114-004-0436-x
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    Let a, b, c, r be fixed positive integers such that a2+b2=cr, min(a, b, c, r) > 1 and 2|r. In this paper we prove that if a≡2 (mod 4), b ≡ 3 (mod 4) c > 3.1037 and r > 7200, then the equation ax+by=cz only has the solution (x, y, z) = (2, 2, r).
  • Wen Jun SUN, Shu WANG
    Acta Mathematica Sinica. 2005, 21(4): 847-854. https://doi.org/10.1007/s10114-004-0512-2
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    In this paper, we obtain the necessary and sufficient conditions on the global existence of all positive (weak) solutions to a nonlinear degenerate parabolic equation with nonlinear boundary condition.
  • Zhi Hua ZHANG (Zhihua ZHANG)
    Acta Mathematica Sinica. 2005, 21(4): 855-864. https://doi.org/10.1007/s10114-004-0419-y
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    Let {ψ μM } be an orthonormal wavelet of L2 (Rd) and the support of a whole of its Fourier transform be

    Under the weakest condition that each |μM| is continuous for , a characterization of the above support of a whole is given.
  • M. KAMARUJJAMA, Dinesh SINGH
    Acta Mathematica Sinica. 2005, 21(4): 865-868. https://doi.org/10.1007/s10114-004-0431-2
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    The authors derive a set of unified representations of the Voigt functions in terms of familiar special functions of Mathematical Physics. Some deductions from these representations are also considered.
  • Guang Fu CAO
    Acta Mathematica Sinica. 2005, 21(4): 869-872. https://doi.org/10.1007/s10114-004-0430-3
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    It is proved that the invertibility of a composition operator on the differential form space for a Riemann surface is equivalent to its Fredholmness. In addition, the Fredholmness of weighted composition operators is discussed.
  • Rong Bao GU, Tai Xiang SUN, Ting Ting ZHENG
    Acta Mathematica Sinica. 2005, 21(4): 873-880. https://doi.org/10.1007/s10114-004-0432-1
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    Let G be a graph (i.e., a finite one-dimensional polyhedron) and f : GG be a continuous map. In this paper, we show that every isolated recurrent point of f is an isolated non-wandering point; every accumulation point of the set of non-wandering points of f with infinite orbit is a two-order accumulation point of the set of recurrent points of f; the derived set of an ω-limit set of f is equal to the derived set of an the set of recurrent points of f; and the two-order derived set of non-wandering set of f is equal to the two-order derived set of the set of recurrent points of f.
  • Shuang Ping TAO, Shang Bin CUI
    Acta Mathematica Sinica. 2005, 21(4): 881-892. https://doi.org/10.1007/s10114-004-0433-0
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    This paper is devoted to studying the initial value problems of the nonlinear Kaup- Kupershmidt equations ∂u/∂t + a1u2u/∂x2 + β∂3u/∂x3 + γ∂5u/∂x5= 0, (x, t) ∈ R2, and ∂u-∂t + a2u/∂x∂2u∂x2 + β∂3 u/∂x3 + γ∂5u/∂x5= 0, (x, t) ∈ R2. Several important Strichartz type estimates for the fundamental solution of the corresponding linear problem are established. Then we apply such estimates to prove the local and global existence of solutions for the initial value problems of the nonlinear Kaup-Kupershmidt equations. The results show that a local solution exists if the initial function u0 (x) ∈ Hs (R), and s ≥ 5/4 for the first equation and s ≥ 301/108 for the second equation.
  • Yu Qun CHEN, Yun FAN, Zhi Feng HAO
    Acta Mathematica Sinica. 2005, 21(4): 893-898. https://doi.org/10.1007/s10114-004-0427-y
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    We characterize the lattice of all ideals of a Morita ring (semigroup) when the corresponding pair of rings (semigroups) in the Morita context are Morita equivalent s-unital (like-unity) rings (semigroups).
  • Ming Chun XU
    Acta Mathematica Sinica. 2005, 21(4): 899-902. https://doi.org/10.1007/s10114-004-0448-6
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    In this paper the following theorem is proved: Every group L3(32m-1)(m≥2) is characterized by its set of element orders.
  • Yan Quan FENG, Ming Yao XU
    Acta Mathematica Sinica. 2005, 21(4): 903-912. https://doi.org/10.1007/s10114-004-0500-6
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    Let p be an odd prime. In this paper we prove that all tetravalent connected Cayley graphs of order p3 are normal. As an application, a classification of tetravalent symmetric graphs of odd prime-cube order is given.
  • Peter V. DANCHEV
    Acta Mathematica Sinica. 2005, 21(4): 913-916. https://doi.org/10.1007/s10114-004-0526-9
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    Let G be a p-mixed Warfield Abelian group and F a field of char F = p ≠ 0. It is proved that if for any group H the group algebras FH and FG are F-isomorphic, then H is isomorphic to G. This presentation enlarges a result of W. May argued when G is p-local Warfield Abelian and published in Proc. Amer. Math. Soc. (1988).
  • Xiao Dong WANG (Xiaodong Wang)
    Acta Mathematica Sinica. 2005, 21(4): 917-922. https://doi.org/10.1007/s10114-004-0489-x
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    The uniqueness of the ADS spacetime among all static vacuum spacetimes with the same conformal infinity is proved for dimension n ≤ 7. For dimension n > 7, the same result is established under the spin assumption.
  • Xiu Hui YANG, Fu Cai LI, Chun Hong XIE
    Acta Mathematica Sinica. 2005, 21(4): 923-928. https://doi.org/10.1007/s10114-004-0439-7
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    In this paper, we investigate the positive solutions of strongly coupled nonlinear parabolic systems with nonlinear boundary conditions:

    Under appropriate hypotheses on the functions a, b, g, h, d and f, we obtain that the solutions may exist globally or blow up in finite time by utilizing upper and lower solution techniques.
  • Chuan LIU, Shou LIN
    Acta Mathematica Sinica. 2005, 21(4): 929-936. https://doi.org/10.1007/s10114-004-0438-8
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    In this paper, we discuss the countable tightness of products of spaces which are quotient simages of locally separable metric spaces, or k-spaces with a star-countable k-network. The main result is that the following conditions are equivalent: (1) b = ω1; (2) t(Sω ×Sω1) > ω; (3) For any pair (X, Y), which are k-spaces with a point-countable k-network consisting of cosmic subspaces, t(X × Y) ≤ ω if and only if one of X, Y is first countable or both X, Y are locally cosmic spaces. Many results on the k-space property of products of spaces with certain k-networks could be deduced from the above theorem.
  • Zeng Jian LOU, Shou Zhi YANG, Dao Jin SONG
    Acta Mathematica Sinica. 2005, 21(4): 949-954. https://doi.org/10.s10114-004-0499-8
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    We give a decomposition of the Hardy space Hz1(Ω) into "div-curl" quantities for Lipschitz domains in Rn. We also prove a decomposition of Hz1(Ω) into Jacobians det Du, uW01, 2 (Ω, R2) for Ω in R2. This partially answers a well-known open problem.
  • Yao Ping HOU
    Acta Mathematica Sinica. 2005, 21(4): 955-960. https://doi.org/10.1007/s10114-004-0437-9
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    A signed graph is a graph with a sign attached to each edge. This paper extends some fundamental concepts of the Laplacian matrices from graphs to signed graphs. In particular, the relationships between the least Laplacian eigenvalue and the unbalancedness of a signed graph are investigated.