The complexity and randomness of linear multi-secret sharing schemes with non-threshold structures

In a linear multi-secret sharing scheme with non-threshold structures, several secret values are shared among n participants, and every secret value has a specified access structure. The efficiency of a multi- secret sharing scheme is measured by means of the complexity a and the randomness . Informally, the com- plexity a is the ratio between the maximum of information received by each participant and the minimum of information corresponding to every key. The randomness is the ratio between the amount of information distributed to the set of users U = {1, …, n} and the minimum of information corresponding to every key. In this paper, we discuss a and of any linear multi-secret sharing schemes realized by linear codes with non-threshold structures, and provide two algorithms to make a and to be the minimum, respectively. That is, they are optimal.     

ON THE DIFFERENCE COUNTERPART OF BRUCK＇S CONJECTURE

In this article, for a transcendental entire function f（z） of finite order which has a finite Borel exceptional value a, we utilize properties of complex difference equations to prove the difference counterpart of Bruck＇s conjecture, that is, if △f（z） = f（z ＋ η） - f（z） and f（z） share one value a （≠α） CM, where η ∈ C is a constant such that f（z ＋η） ≠ f（z）,then
△f（z）-a/f（z）-a=a/a-α.     

含参变量超越方程及高次方程迭代法求解的初值选取方法

针对含参变量超越方程及高次方程迭代法求解时初值选取困难的问题,通过分析迭代方程收敛速度随参变量的变化规律,提出了以参变量定义域内收敛速度最慢处方程的解为迭代初值,并将该含参变量的超越方程或高次方程在此处进行二阶泰勒级数展开,舍去高阶余量,进一步求解该二次方程得到另一种初值.方法的适用条件是迭代方程必须是收敛的.实例计算表明,将初值代入迭代公式仅需一次迭代即可得到精度较高的近似计算公式,可用于含参变量的超越方程及高次方程迭代求解.     

复微分-差分方程组的整函数解

利用值分布理论,研究了一类n阶复微分-差分方程ω~(n)(z)~2+[αω(z+c)-βω(z)]~2=1和复微分-差分方程组■是否存在有限级整函数解的问题.本文推广并改进了高凌云和刘凯等人的结果.     

关于超越代数体函数的增长与其亏函数个数的关系

设 f(z)为 n 值的超越代数体函数,如果存在 n+1个整函数φ_i(i=0,1,2,…,n)满足T(r,φ_i)=0{T(r,f)},r→∞且δ(φ_i,f)=1(i=0,1,…,n),则 f(z)的级λ为正整数或无穷且是正规增长的.     

金融市场极端日收益数据的广义Pareto分布拟合

本文基于极值理论和方法建立了上证综合指数极端日收益率的广义Pareto模型,并利用所得的模型计算出日收益率的返回水平及其上尾概率。将估计的日收益率模型比较得出,在实施涨跌停板前,日收益率的上尾明显厚于实施涨跌停板后的上尾,说明了实施该制度可以有效的控制股票市场的投机现象,从而降低投资者的收益损失风险。     

关于Clunie的一个结果

设f(z)是超越整函数，α为异于零的有穷复数，Clunie证明了f′f-α有无穷多个零点。本文对f′f-α的零点个数给出定量的估计，其中一个结果是δ（α，f′f)≤6/7。     

关于f(k)f-a的零点之猜测

本文完全证明了[1]中的一个猜测，设f为超越整函数，k为非负整数，则f^(k)f仅可能有的Picard例外值是0，由此还得到整函数族的一个正规定则。     

复高阶微分方程的解

利用亚纯函数的Nevanlinna值分布理论以及最大模原理,讨论了一类复高阶微分方程的代数体解以及一类复高阶微分方程组的超越亚纯解的存在性问题,得到了两个结论.还推广了一些文献的结论,例子表明该文的结论是精确的.     

EXCESS FUNCTIONS OF RAYS ON COMPLETE NONCOMPACT MANIFOLDS

This paper gives an estimate of excess functions of rays on complete noncompact manifolds. By using this estimation, the authors can get the results in [3] as corollaries, which asserts that a complete manifold is diffeomorphic to R^n under some curvature and pinching conditions. At last, they obtain a refinement of them with extra Ricci condition.