中国科学院数学与系统科学研究院期刊网

15 December 1994, Volume 10 Issue 4
    

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  • Zheng Zukang
    Acta Mathematica Sinica. 1994, 10(4): 337-347. https://doi.org/10.1007/BF02582030
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    Let X1,X2,...,Xn be a sequence of nonnegative independent random variables with a common continuous distribution functionF.Let Y1,Y2,...,Yn be another sequence of nonnegative independent random variables with a common continuous distribution function G,also independent of {Xi}.We can only observe Zi=min(Xi,Yi),and .Let H=1-(1-F)(1-G) be the distribution function of Z.In this paper,the limit theorems for the ratio of the Kaplan-Meier estimator Ŝn(t) or the Altshuler estimator Sn(t) to the true survival function S(t) are given.It is shown that (1)P(n)=1 i.o.)=0 if FH)<1 and Pn=0 i.o.)=0 ifGH) > 1 where δ(n) is the corresponding indicator function of and have the same order a.s.,where {Tn} is a sequence of constants such that 1-H(Tn)=n(logn)β(log logn)γ.
  • Yang Jin-gen
    Acta Mathematica Sinica. 1994, 10(4): 348-361. https://doi.org/10.1007/BF02582031
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    This paper displays the relation between the Dynkin diagrams of rational double points on a normal quintic K3 surface with one triple point and the positive definite lattices of rank 16 with discriminant 5.Under certain conditions,the former can be obtained from the Dynkin diagrams of the latter by a succession of two elementary transformations.
  • Qiu Weiyuan
    Acta Mathematica Sinica. 1994, 10(4): 362-368. https://doi.org/10.1007/BF02582032
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    We show that the set of λ-values for which λ exp(z) does not have stable regions has Hausdorff dimension two,and that the set of λ-values for which λsin(z) does not have stable regions has a positive area.
  • Jia Chaohua
    Acta Mathematica Sinica. 1994, 10(4): 369-387. https://doi.org/10.1007/BF02582033
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    In this paper,we shall prove that for a sufficiently large odd number N,the equation has solutions.
  • Jiang Qibao
    Acta Mathematica Sinica. 1994, 10(4): 388-395. https://doi.org/10.1007/BF02582034
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    Several new results on the indices of singular points in a polynomial vector field are proved in this paper (see Theorems 1-5).
  • Chen Hao
    Acta Mathematica Sinica. 1994, 10(4): 396-400. https://doi.org/10.1007/BF02582035
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    Deformation theory is an important aspect of the study about isolated singularities.The invariant called irregularity is very useful in the study on the deformation of isolated singularities.In this note we give an optimal upper bound for a class of surface singularities by the computation of cohomology.Moreover a sufficient condition is given for the positivity of irregularity of some simple hyperbolic surface singularities.Therefore a class of surface singularities with non-rigid deformation is constructed.
  • U-Hang Ki, Nam-Gil Kim
    Acta Mathematica Sinica. 1994, 10(4): 401-409. https://doi.org/10.1007/BF02582036
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    The purpose of this paper is to define a ruled real hypersurface of a complex space form Mn(c),c≠0,and to give characterizations of this hypersurface by the infinitesimal affine transformation of the structure vector field induced on the hypersurface.
  • Zhu Daxin
    Acta Mathematica Sinica. 1994, 10(4): 410-414. https://doi.org/10.1007/BF02582037
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    We consider the following Hamiltonian system:

    where VC2(Rn{0},R) is an even function.By looking for closed geodesics,we prove that (HS) has a nonconstant periodic solution of prescribed energy under suitable assumptions.Our main assumption is related with the strong force condition of Gordon.
  • Sun Jiong
    Acta Mathematica Sinica. 1994, 10(4): 415-427. https://doi.org/10.1007/BF02582038
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    The author considers the embedding problem of weighted Sobolev spaces Hpn in weighted Ls spaces Ls,r,and some sufficient conditions and necessary conditions are given,when weight functions satisfy certain conditions.The author uses the results obtained to the qualitative analysis of the spectrum of 2n-order weighted differential operator,and gives some sufficient conditions and necessary conditions to ensure that the spectrum is discrete.
  • Zhang Linghai
    Acta Mathematica Sinica. 1994, 10(4): 428-438. https://doi.org/10.1007/BF02582039
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    This paper is a discussion of global solutions to the initial value problems for generalized Banjamin-Bona-Mahony equations.Some long time behaviors of the solutions are presented with the initial data in some certain Sobolev spaces.We employ the method of integral estimate,Fourier transform and Gronwall's inequality.
  • Liu Kai, Yan Jia-an
    Acta Mathematica Sinica. 1994, 10(4): 439-445. https://doi.org/10.1007/BF02582040
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    Let (S)⊂L2(S′(IR),μ)⊂(S)* be the Gel'fand triple over the white noise space (S′(IR),μ).Let (en,n>-0) be the ONB of L2(IR) consisting of the eigenfunctions of the s.a.operator .In this paper the Euler operator ΔE is defined as the sum ,where ∂i stands for the differential operator Dei.It is shown that ΔE is the infinitesimal generator of the semigroup (Tt),where (Ttψ)(x)=ψ(etx) for ψ∈(S).Similarly to the finite dimensional case,the λ-order homogeneous test functionals are characterized by the Euler equation: Δψ.Via this characterization the λ-order homogeneous Hida distributions are defined and their properties are worked out.