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1.
引入了双重Ockham代数的概念,讨论了同分关系、次直不可约代数及其子结构问题.证明了双重Ockham代数具有同余扩张性质,即对代数(L;f,g),其子集M(f,g)={x∈L|f(x)=g(x)}是L的子代数.  相似文献   

2.
在算子B=x.d/dx作用下,欧拉方程xndny/dxn+P1x^n-1dn-1/dx^n-1+...+Pn-1xdy/dx+Pny=f(x),其中P1,P2,...,Pn为常数),可化为:(A^nB+P1A^n-1B+...+A^0B)y=f(x)。并简记为L(B)y=f(x),把B待定系数k,则L(B)=0即为欧拉方程的特征方程,从而可求出齐次方程的通解yH,再根据L(B)的逆算子性质求欧拉方程的特解yp=1/L(B)f(x),便求得欧拉方程的通解:y=yH+yp。  相似文献   

3.
一类三次Kolmogorov系统的定性分析   总被引:1,自引:0,他引:1  
研究了一类三次Kolmogorov系统x=x(A0+A1x-A3x^3+A2y),yd=dy(-1+x^2-6((*);x=x(A0+A2x-A3x^2-A2y),y=y(-1+x^2-y)(**)。得到:(1)A0>A2,A2<A3<A1时,系统(*)在第一象限内不存在极限环;(2)当A3>A2,A0+A2>1/2时,系统(**)在第一象限内是全局稳定性的。  相似文献   

4.
Lurie型鲁棒控制系统的绝对稳定性   总被引:7,自引:0,他引:7  
在实数R上一切闭区间组成的集合和区间矩阵的集中中引进了代数运算,讨论了Lurie型直接鲁棒控制系统x=G「B,C」x+G「R,S」f(σ);σ=c^Tx,f(.)∈K「0,∞」和间接鲁棒控制系统x=G「B,C」x+G「R,S」f(σ);σ=c^Tx-.f(.)∈K「0,∞」display structure  相似文献   

5.
本文对扭仿射Lie代数g(x^(2)n)(xN=A2I,A21-1或D1+1)的一类子代数的根子集进行了刻划进而得到了这类子代数的结构与分类。  相似文献   

6.
双重Ockham代数的同余核吴丽云(广东民族学院计算机科学系,广州510633;作者,女,41岁,讲师)双重Ockham代数是一个具有(2,2,1,1,0,0)类型的代数(L;∧,∨,f,g,1,0),其中(L;∧,∨,1,0)为有界分配格,(L;∧...  相似文献   

7.
本文证明了丢番图方程z^4-py^4=及x^2-py^4=4(p为奇素数)无正整数解;在D〉0且不被10K+1形素因数整阶时,方程x^5-1=Dy^2在x≠(mod20)时反有正整数解D=2,z=3,y=11。  相似文献   

8.
设Ψ:Ω→R^n,1是一个C^2-映射,则Ψ是一个Lorentz共形映射的充分且必要条件:存在一个正实函数K(x):Ω→R+,使得「K(x)」^-1JΨ是一个Lorentz矩阵,并由此得到,如果D^n-1/n+1是一常数(D=detJΨ),则Ψ的第一个分量是波动方程q^2u/qx^2n+1=n/∑i=a^2u/ax^2i的正则解。  相似文献   

9.
本文考虑时滞差分方程xn+1=axn+β^.xn/1+x^kn-1,n=,1,…。(1)的全局吸引性,这里l是正整数,K∈(0,∞),并且0〈α〈1〈α+β。部分地回答了文献「1」中提出一分开问题11;1.(b),获得了方程(1)的一切{xn}收敛于正常平衡常数N=(α+β-1)/1-α)^1/k的充分条件。  相似文献   

10.
一类对称函数不等式的加强,推广及应用   总被引:1,自引:0,他引:1  
EK(x),Ek(1-x)和Ek(1+x)分别表示x1,…,xn;1-x1,…,1-xn和1+x1,…,1+xn的第k个初等对称函数,借助控制不等式理论中强和推广了关于对称函数的一类不等式的结论,主要结果为:1)(C^kn-1)^r,s^rka≤Ek(s-x^a)-λE^rk(X^a)≤(C^kn)s^rha((1-1/n^a)^kr-λ(1/n^a)^kr),其中n≥3,Xi〉0,i=1,…,n  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.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
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   

14.
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   

15.
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   

16.
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   

17.
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   

18.
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   

19.
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   

20.
<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   

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