群环的幂等稳定度1

设a∈R,如果对环R元素b,满足aR+bR=R,则存在幂等元e∈R,使得a+be有左逆,那么称元素a有幂等稳定度1(记为isr(a)=1).如果对于R中的所有元素a,都有isr(a)=1,那么称环R有幂等稳定度1(记为isr(R)=1).证明了若R是半完全环,G是初等阿贝尔p-群,则isr(RG)=1.另外,若isr(R)=1,G是局部有限p-群,且p∈J(G),则isr(RG)=1.     

型为2~n的框架幂等Schrder拟群(英文)

在一个v阶不完全的幂等Schro¨der拟群中去掉vi个阶为hi的子拟群(1≤i≤k),如果这些子拟群是不相交的且是生成的(即:∑1≤i≤kvihi=v),则称这个v阶拟群为框架幂等Schro¨der拟群,并记为FISQ(hv11h2v2…hvkk).业已证明,FISQ(1n)存在当且仅当n≡0,1(mod 4)且n≠5,9.本文报道了除n=8作为可能的例外,FISQ(2n)存在的充分必要条件是n≥5且n≠6.     

带非局部条件的分数阶差分方程边值问题三个正解的存在性

利用Leggett-Williams不动点定理,得到分数阶离散边值问题-Δ~vy(t)=λh(t+v-1)f(y(t+v-1)),y(v-2)=Ψ(y),y(v+b)=Φ(y)至少存在三个正解的充分条件,其中1v≤2,t∈[0,b]_(N_0):={0,1,…,b},f:[0,∞)→[0,∞)是连续函数,h:[v-1,v+b-1]N_(v-1)→[0,∞),Ψ,Φ:C([v-2,v+b]N_(v-2))→R是给定的函数,其中Ψ,Φ为线性函数,λ为一正参数。     

强Quasinil Quasi-clean环和Quasi-polar环

设R是一个环，称环R的元素e为拟幂等元，如果存在R的某个中心单位k,使得e²=ke。若R中的每个元素都存在拟幂等元e∈R,q∈R^qnil使得e∈comm²(a),并且a=e+q,则称环R是强quasinil quasi-clean环。若环R中每个元素a都存在一个拟幂等元e∈R使得e∈comm²(a),a+e∈U(R)且ae∈R^qnil,则称R是拟quasi-polar环。本文首先证明拟quasi-polar环与quasi-polar环等价，在此基础上进一步证明强nil quasi-clean环是强quasinil quasi-clean环，强quasinil quasi-clean环是quasi-polar环，但反之均不成立。     

型为2n的框架幂等Schr(o)der拟群

在一个v阶不完全的幂等Schroder拟群中去掉vi个阶为hi的子拟群（1≤i≤k），如果这些子拟群是不相交的且是生成的（即：∑1≤i≤k=v），则称这个v阶拟群为框架幂等Schroder拟群。并记为FISQ（ h1^v1h2^v2…hk^vk）．业已证明，FISQ（1^n）存在当且仅当n=0，1（mod4）且n≠5，9．本文报道了除n=8作为可能的例外，FISQ（2^n）存在的充分必要条件是n≥5且n≠6．     

几乎SS-嵌入子群对有限群p-幂零性的影响

称子群H为在有限群G中几乎SS-嵌入的,如果存在G的s-拟正规子群T使得HT在G中s-拟正规且H∩T≤HseG,其中HseG为包含于H的G的所有s-拟正规嵌入子群生成的群。记Md(P)={P1,P2,…,Pd}为素数幂阶群P的极大子群的集合,满足∩di=1Pi=Φ(P)。本文考察了Md(P)中元素具有上述性质时对有限群p-幂零性的影响,并推广了若干相关的新近结果。     

定义在三个互素因子链上的交错幂GCD和交错幂LCM矩阵的整除性

设S={x_1,x_2,…,x_n}是由n个不同的正整数组成的集合,并且设a为正整数.如果一个n阶矩阵的第i行j列元素定义为(-1)~(i+j)(x_i,x_j)~a,其中(x_i,x_j)_a表示S中的元素x_i与x_j的最大公因子的a次幂,则称这个矩阵((-1)~(i+j)(x_i,x_j)~a)是定义在S上的a次幂最大公因子(GCD)交错矩阵,简记为(AS~a).类似可定义a次幂最小公倍数(LCM)交错矩阵((-1)~(i+j)[x_i,x_j]~a),简记为[AS~a].在本文中,设S由三个互素的因子链构成,且1∈S.作者证明了如下结果成立:(1)若a|b,则det(AS~a)| det(AS~b),det[AS~a]| det[AS~b],det(AS~a)| det[AS~b];(2)在n阶整数矩阵环M_n(Z)中,若a|b,则(AS~a)|(AS~b),[AS~a]|[AS~b],(AS~a)|[AS~b];若ab,则(AS~a)(AS~b),[AS~a][AS~b],(AS~a)[AS~b].     

D8p的连通3度Cayley有向图的正规性

称有限群G的Cayley（有向）图X是正规的,如果G的右正则表示R（G）正规于图X的全自同构群Aut（X）.该文主要研究8p阶二面体群G∶=D8p=〈a,b a4p=b2=1,b-1ab=a-1〉的连通3度Cayley有向图X∶=Cay（G,S）的正规性.并证明：（1）若p=2时,Cayley（有向）图X不正规当且仅当S~{b,a,a5}和S~{b,ba,bak}（k=3,4,5,6）.（2）若p为奇素数,Cayley（有向）图X不正规当且仅当S~{b,a,a2p＋1}和S~{b,ba,bak}（k=2p,2p＋1）.     

常数H(a,X)与一致正规结构

主要得到常数H(a,X)=sup{‖x+y ‖∧‖(a+1)x-y ‖:x∈S(X),y,y-ax∈B(X),a≥0}的一些性质,并证明了其与一致正规结构的关系定理:若X满足H(a,X)＜(3+a)/2,则对某个a∈[0,1],X具有一致正规结构.     

拟Banach空间正交的右存在性和左存在性

给出了一类新的正交性—拟Banach空间正交性,它是正交性的一种推广。首先,建立了拟Banach空间中两个元素的正交性与线性泛函之间的关系,并给出拟Banach空间正交的充要条件,即设X是实数域R上的拟Banach空间,有界线性泛函f∈SX*=f∈X*:‖f‖=1{},非零元素x∈X,H={h∈H:f(h)=0}是X的超平面,则f(x)=‖x‖等价于x⊥H;然后,给出了拟Banach空间正交右存在性和左存在性的充分条件;最后,举例说明了拟Banach空间中任意两元素不一定有正交右存在性。     

Hopf拟群的代数形变

利用2-余循环对原有Hopf拟群的结构进行代数形变,进而构造出新的Hopf拟群,并讨论了新构造的Hopf拟群上的余拟三角结构与原有Hopf拟群上的余拟三角结构之间的关系,推广了Hopf代数中的相应结论.     

拟群在构作图K_(m+2)\K_m的图设计中的应用

利用拟群给出所需的带洞图设计,再结合一些小阶数的图设计的存在性,得到了关于图Gm=Km+2、Km的图设计的一些存在性结果.从而展示了拟群在解决图设计问题中的应用.     

拟Hopf-模上的Rota-Baxter代数

把Run-qiang Jian文中的H为Hopf代数的情况推广到H为Hopf(余)拟群,其主要结论:设H是Hopf拟群,(M,φ)是一右拟H-Hopf模代数,则(M,P)是权为-1的Rota-Baxter代数.     

Yetter-Drinfeld拟模范畴上的Hopf拟模

设L是域k上的一个有双射对极S_L的Hopf拟群.利用对偶的方法证明:如果H是一个Yetter-Drinfeld拟模范畴■上的有限维Hopf拟群,则其线性对偶空间H*是■上的一个Hopf余拟群,且其Pontryagin对偶空间H**■H也是一个Hopf拟群;进一步,H*有一个■上的右H-Hopf拟模结构。     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

Perspherical Approaches for Electrons in Atoms and Charged Excitons in Quantum Wells

Instead of following Fock’s expansion,we solve the Schrodinger equation for some quantum mechanical manybody systems such as electrons in atoms and charged excitons in quantum wells in a similar way in hyperspherical coordinates by expanding the wave functions into orthonormal complete basis sets of the hyperspherical hannonics(HHs)of hyperangles and generalized Laguerre polynomials(GLPs)of the hyperradius.This leads the equation to     

Advances in broadband wireless communications under high-mobility scenarios

Future mobile communication systems aim at providing very high data transmission rates, even in high-mobility scenarios such as high-speed wheel-track trains, maglev trains, highway vehicles, airplanes, guided missiles or spacecraft. A particularly important commercial application is the strong and increasing worldwide demand for high- speed broadband wireless communications （up to 574.8 km/ h test speeds or 380 km/h commercial speeds） in railways, providing data, voice and video services for applications such as onboard entertainment services to passengers, train control, train dispatch, train sensor status handling and sur- veillance. In such high-mobility scenarios, there are a number of communication challenges, including fast hand- over, location updating, high-speed channel modeling, estimation and equalization, anti-Doppler spreading tech- niques, fast power control, and dedicated network architec- ture. Because signal transmission in very high-speed scenarios will inevitably experience serious deterioration, it is imperative to develop key broadband mobile communi- cation techniques for such high-speed vehicles.