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1.
设π=(d_1,d_2,…,d_n)是非负整数序列,π_1,π_2是将π的所有元素划分为两部分后的两个子序列.如果-1≤|π_1|-|π_2|≤1,则称π_1,π_2是π的一个平衡二部划分,其中|π_i|(i=1,2)表示π_i中的元素数目.设k和n是两个正整数,π=(k~n)是k-正则可图序列.本文确定了ψ_(max)(π)的值和ψ_(min)(π)的值.  相似文献   

2.
设P为域GF(q)上的n(n≥3)维射影空间PG(n,q)中的一个点,L是PG(n,q)中过P的一条线。取包含L的超平面组成的集合为信源集S,与L的交为{P}的超平面组成的集合为编码规则集E。与L的交为{P}的n-2-子空间组成的集合为信息集M。对任意π1∈S,π2∈E,定义f(π1,π2)=π1∩π2,得到一类Cartesian认证码,并计算了这个码的参数。假设编码规则按照一种均匀概率分布被选取,则成功模仿攻击的概率PI和成功替换攻击的概率PS也被计算。  相似文献   

3.
把线段、方体自映射混沌集合的Hausdorff维数的有关结果推广到n方体上,证明在C~0(I~n)中存在一个剩余集R,使对每一f∈R,如果集合C?I~n对f是Li-Yorke混沌的,则dim_H(C)≤n-1.对于高维笛卡尔积的情形,也得到类似的结果,即在C~0(I~(ni),I~(ni))中存在一个剩余集Ri,使得对于每个f_i∈R_i,i=1,2,若集合C_i?I~(ni)对于f_i而言是Li-Yorke混沌的,则dim_H(C_1×C_2)≤n-1.  相似文献   

4.
本文给出逻辑程序的与并行推理模型LPT(Loosely-Linked Proof Tree)的基本思想.LPT将基于一阶谓词演算的逻辑程序的执行定义为以主动求值方式进行的与并行推理,具有许多重要性质.这里,对逻辑式语言无过多限制. 定义1 在关系R的定义子句R:——R_1,…,R_n,若存在一个变量x,x既是R_i的出变量,又是R_j的入变量,则称R_i关于R_j数据相关. 定义2 在关系R的定义子句R:——R_1,…,R_n,若存在变量x_1,…,x_S,且R_(ij)关于x_(j+1)与R_(ij+1)数据相关,则称R_(io),…,R_(is)构成长度为S的单向信道,记为(R_(io)…,  相似文献   

5.
在Harrison意义下的无界报酬函数折扣模型下,本文讨论了最优策略的几个性质和它的结构。本文证明了:若π~*=(π_1~*,π_2~*,…)是该模型的最优策略,则π_1~(*∞),(π_1~*,…,π_n~*)~∞与(π_1~*,…,π_n~*,π_1~*,π_2~*,…)(n≥1)都是最优策略;给出π_n~*也构成最优随机平稳策略的条件和修改方法;策略π~*=(π_1~*,π_2~*,…)是最优的当且仅当它在任何时刻可达的状态上都必须选取最优决策;最后指出π_0~(*∞)为最优随机平稳策略的充要条件是决策规则π_0~*是若干个最优平稳策略f_n~∞的决策函数f_n的凸组合。从而较完满地解决了Harrison无界报酬意义下折扣模型的最优策略结构问题。  相似文献   

6.
缺项整函数的奇异方向的分布   总被引:2,自引:2,他引:0  
本文着重讨论缺项整函数的Julia方向和Borel方向的分布,并获致以下两个有趣的结果。定理1.设f(Z)=∑C_nZ~(λn)为一整函数,且满足缺项条件:■ (A)则对于任一条从原点出发的半直线J:arg z=θ_0(0≤θ_0<2π),或者J:arg z=θ_0为f(z)的Julia方向;或者存在正数ε(θ_0),使得■ (B) 定理2.设f(z)=∑C_nZ~(λn)为一满足缺项条件(A)的正规增长整函数。若f(z)的级λ为正数或无穷大,则对于任一条从原点出发的半直线B:arg z=θ_0(0≤θ_0<2π),或者B:arg z=θ_0为f(z)的Borel方向;或者存在一正数ε(θ_0)及集合E满足lim mes(E(z;|z|≥r))=0,使得■ (C)  相似文献   

7.
本文,我们将引进n—Hall塔群和严格π—闭群的概念,这两个概念是Sylow塔群和严格p—闭群相应的推广。首先,我们证明了这两类群的一系列的性质;然后利用这些性质证明得到了有限超可解群的一个充要条件。本文得出的主要结果是: 主要定理有限群G为超可解群的充要条件是存在π(G)的某划分Π=(π_1,…,π_r),使得 (1)G有Π—Hall塔,且G的Hall π_i—子群H_i为幂零;又当|π_i|>1时,H_i的上中心列中每商因子为循环,1≤i≤r。 (2)对G之任一Hallπ_i一子群H_1,N_G(H_i)/CG(H_i)为严格π_ 1—闭,1≤i≤r。  相似文献   

8.
本文应用能带结构的多谷模型,对N型硅在[100]方向的压阻效应进行了理论分析。当沿N型硅晶体的[100]轴施加压力并分别在[100]和[010]方向加电场时所引起的电导率变化的主要原因是:电子在能谷之间转移时,电子的迁移率发生变化。由此推导出N型硅的纵向压阻系数π_(11)与横向阻压系π_(12)之间的关系是: π_(12)=-1/2π_(11)且π_(12)的符号是“正”,π_(11)的符号是“负”。这一结果与C.S.Smith的实验测量数据吻合。  相似文献   

9.
本文利用“素数的表示法定理”和同余、二次剩余的性质,证明了 n~2+C 型素数的个数π_1(X_1)与π(X)关系的一个近似公式。  相似文献   

10.
在文献[1],C.C.Chang定义了L_(ω_1ω_1)语言的可构成集类C,并且在ZFC中讨论了C的若干性质.本文建立了相对于集合A的用语言L(ω_1ω_1)所刻划的可构成集类C[A],并且得出了其若干性质.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

13.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

14.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

15.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

16.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

17.
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the  相似文献   

18.
Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of  相似文献   

19.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

20.
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