Global well-posedness and blow-up for the hartree equation

For 2 γ min{4, n}, we consider the focusing Hartree equation iu_t+ △u +(|x|~(-γ)* |u|~2)u = 0, x ∈ R~n.(0.1)Let M [u] and E [u] denote the mass and energy, respectively, of a solution u, and Q be the ground state of-△ Q + Q =(|x|~(-γ)* |Q|~2)Q. Guo and Wang [Z. Angew. Math.Phy.,2014] established a dichotomy for scattering versus blow-up for the Cauchy problem of(0.1) if M [u]~(1-s_c)E [u]~(s_c) M [Q]~(1-s_c)E [Q]~(s_c)(s_c=(γ-2)/2). In this paper, we consider the complementary case M [u]~(1-s_c)E [u]~(s_c)≥ M [Q]~(1-s_c)E [Q]~(s_c) and obtain a criteria on blow-up and global existence for the Hartree equation(0.1).     

FP-内射模决定凝聚环与IF环

我们在§2.中证明了 1.可换环是Noether环?平坦模与内射模的张量积是内射模。本文的其余部分考虑用FP-内射性质来刻划凝聚环、CF环及IF环,主要结果有: 2.对于环R,下述各条等价: (1) R是左凝聚环。 (2) 对于任意有限表示模_RM,FR-内射模_RN,都有Ext_R²(M,N)=0 (3) 若N₁?_RN都是FP-内射的,则N/N₁是FP-内射     

地下水污染中一离子反应数学模型的有限元方法

1　引　　言在地下水含水层中 ,污染物随地下水运移并常常发生各种化学反应 [1 ] .描述地下水含水层中一类阳离子交换反应 m M1 +r M2 k2k1 r M2 +m M1 的数学模型[2 ] 为 : s1 t- dΔs1 =f1 ,　　 x∈Ω ,t∈ J (1.1a) s2 t- dΔs2 =f2 ,　　 x∈Ω ,t∈ J (1.1b) c1 t+ρ s1 t- DΔc1 =0 ,　　 x∈Ω ,t∈ J (1.2 a) c2 t+ρ s2 t- DΔc2 =0 ,　　 x∈Ω ,t∈ J (1.2 b)其中 Ω R2为具有光滑边界的有界区域 ,J=(0 ,T].这里 D>d>0为扩散系数 ,ρ>0为固体颗粒密度 ,均为常数 .根据 [1,2 ]应有 :f1 =m[k1 Rm1 Rr2 cm1 sr2 -…     

(2,2,…,2)型数域的判别式密度

(2,2,…,2)(n个2)型数域即是由n个二次域合成的Q的2~n次扩域,亦称n重二次域.问题是计算判别式等于d(以及小于X)的n重二次域的个数J_n(d)(以及N_n(x)).文献[1]和[2]分别解决了n=2和3的情况.本文在这种域的结构的基础上,解决了一般的n的问题:明显算出了J_n(d),定出N_n(X)=a_nX^21-n·log^2n-2X+O(X^21-nlog^2n-3X),其中a_n是已知常数.文献[1]和[2]的结果是本文结果n=2,3的特殊情况.     

关于实二次域的类数(Ⅱ)

本文推广了文献[1]的结果,提供了实二次域类数等于1的另一个充要条件,文献[1]是这里的一个特例,特别,对素数p=4n²+1(n>1),域K=Q(p×1/2)的类数等于1的充要条件是这儿ζ_K(s)是域K的ζ-函数.     

关于贝尔*1、达布函数线性运算的不封闭性

R.J.O＇Mallcy曾做了不少工作[1][2],但是在“贝尔^*1、达布函数的插值”一文[1]所得到的结果却是不真的.文[1]定理2指出:“设f,g是贝尔l、达布函数,如果对于任意的x₀,ε>0.δ>0,集{x||f(x)-f(x₀)│<ε,|g(x)-g(x₀)<ε|∩U(f,g)∩(x₀+x₀+δ)≠?,且对x₀的左半邻域相应陈述同样成立，其中U(     

2—调和映照的复合映照

本文研究了Ricmann流形间2—调和映照的复合映照的性质及其应用.按照J.Eells和L.Lemaire在文献[1]中的设想,姜国英在[2]中通过计林某一泛函数的第一、二变分的方法,探讨了Riemann流形间的2—调的映照f:M→N,它的张力场τ(f)满足方程:(?)其中{e_k}为M的局部标准正交林架场.A^*A是向量丛f^-1TN上的迹Laplace算子,R^N是N的曲率算子.当M紧致时,2—调和映照f恰是使2—能量泛函(?)取临界值的映射.显然,它是调和映照的一种推广.本文研究了Ricmann流形间2—调和映照的复含映照的一个性质,并给出了它的应用.     

Rees环的入射维数

设 A 是左、右 Noether 环,x 是 A 的中心正则元.A_x 表示 A 关于乘闭子集{1,x,x²,…}的局部化.M 是 A-模且 x 是 M 的非零因子.本文确定了入射维数Id_A(M),Id_Ax(M_x)与 Id_A/xA(M/xM)三者之间的等式关系,并把结果应用于滤环(filtered ring)的 Rees 环,得到了 Ekstr(?)m 的两个结果的统一形式和改进,同时推广了 Li Huishi,M.Van den Bergh 和 F.Van Oystaeyen 的相应结果.     

Sp(2n,F2)中含长根子群的极大子群系

All maximal subgroups in PS_p(2n,F) which contain long root subgroups have been determined in [1] for F≠F₂ and will be determined here for F = F₂. Other than the three types of reducible or imprimitive maximal subgroups listed in[l], we have here the orthogonal groups O(2n,F₂,Q) and the symmetric groups S_2n+2 (n even and ≥4) to complete our list.     

交错环的最大(Von Neumann)正则理想

结合环R中一个元素a称为(Von Neumann)正则的,若有某个x∈R使得axa=a.R的一个理想I称为(Von Neumann)正则的,若I中每个元素都是R的(Von Neumann)正则元。 Brown和McCoy在[1]中证明了任意结合环R存在一个唯一最大的(Von Neumann)正则理想M(R),且作了特征刻划。 Tsai在[2‘3]中把这些结果推广到Jordan环。 最近,本文作者在[4]中指出:这些性质在弱T_N-环中也成立。 本文说明这些结果也可推广到交错环A,可以得到:任意交错环A存在一个唯一最大的(Von Neumann)正则理想M(A);M(A)有和结合环一样的特征刻划;M(A)是     

关于分次本质右理想

设 Ｒ是 Ｇ－分次,本文讨论了环 Ｒ的相关环 Ｒ,Ｒ＃ Ｇ^*, Ｒｅ, Ｑ（Ｒ）, Ｒ^G, Ｒ*Ｇ及 Ｒ的正规化扩张Ｓ的非奇异性,右一致性,右基座之间的关系．当Ｒ_Ｒ是ＹＪ－内射模时,证明了Ｊ（Ｒ）＝Ｚ（Ｒ）。     

有限局部环Z/q~kZ上矩阵广义逆的几个计数结果

设 R =Z/ qk Z是模整数 qk的有限局部环 ,其中 q是素数 ,k>1 .对 R上给定的 n阶矩阵 A,设 W1={X∈ Mn( R) |PAXP- 1=Q- 1XAQ, 1 P,Q∈ GLn( R) },W2 ={X∈ Mn( R) |AX =XA},W3={X∈ Mn( R) |AXA =A},W4 ={X∈ Mn( R) |XAX =X}.若 Wi≠Φ( i=1 ,2 ,3 ,4) ,用 n( Wi)表示 Wi中所有元素的个数 ,主要计算出 n( Wi) ( i =1 ,2 ,3 ,4)     

Differential geometry on almost tangent manifolds

Summary We start from a tensor field Q of type (1, 1) defined in a2n-dimensional manifold M which satisfies Q ²⁼⁰ and has rank n. The tensor field Q defines an almost tangent structure in M. We then introduce another tensor field P of the same type and having properties similar to those of Q. We then define and study the tensors H=PQ, V=QP, J=P−Q, K=P+Q, L=PQ−QP, (J, K, L) defining an almost quaternion structure of the second kind on M. We study the differential geometry on almost tangent manifolds in terms of these tensors. To ProfessorBeniamino Segre on his seventieth birthday Entrata in Redazione il 7 giugno 1973.     

Die absteigende Loewy-Länge von Endomorphismenringen

We give an upper bound for the descending Loewy length of the ring S=End(M), where M is a semi-artinian R-module satisfying some extra-conditions.In case M is of finite length, our main result specializes to the following result, which improves a theorem of Smalø ([3]): The index of nilpotency of Ra(S) is bounded by the number max{l_A¦A is a simple R-module occuring in the socle of M}, where l_A denotes the number of times the isomorphism type of A occurs as a factor in a composition chain of M.     

The growth of solutions of <Emphasis Type="Italic">f</Emphasis>″ + e<Superscript>-z</Superscript><Emphasis Type="Italic">f</Emphasis>′+ Q(z)<Emphasis Type="Italic">f</Emphasis> = 0 where the order (Q) = 1

This paper investigates the growth of solutions of the equation f″ + e^-z f′ + Q(z)f = 0 where the order (Q) = 1. When Q(z) = h(z)e^bz, h(z) is nonzero polynomial, b ≠ - 1 is a complex constant, every solution of the above equation has infinite order and the hyper-order 1. We improve the results of M. Frei, M. Ozawa, G. Gundersen and J. K. Langley.     

ON EULER CHARACTERISTIC OF MODULES~(**)

This paper gives a characteristic property of the Euler characteristic for IBN rings. The following results: are proved. (1) If R is a commutative ring, M, N are two stable free R-modules, then χ(MN)=χ(M)χ(N), where χ denotes the Euler characteristic. (2) If f: K_0(R)→Z is a ring isomorphism, where K_0(R) denotes the Grothendieck group of R, K_0(R) is a ring when R is commutative, then f([M])=χ(M) and χ(MN)=χ(M)χ(N) when M, N are finitely generated projective R-modules, where.the isomorphism class [M] is a generator of K_0(R). In addition, some applications of the results above are also obtained.     

关于环的交换性定理

令R为有单位元的结合环,M(R)=N(R)∪J/(R).证明了如果存在正整数m使得所有x,y∈_R\M(R)均满足(xy)~k=x^ky^k(其中k=m,m+1,m+2);或者使得所有x,y∈R\M(R)均满足(xy)~k=y^kx^k(其中k=m-1,m,m+1为正整数),那么R是交换环.     

On the Structure of Primitive Rings with v-Socles

In this paper, we generalize the classical structure theorem and isomorphism theorem of primitive rings. Let u be a primitive ring, then u can be regarded as a dense subring of linear transformations in a vector space M. Lei \Omega be the ring of all linear transformations of M, we define (BV=^TV[\ 11, where Tv is the ideal of Q which contains all linear transformations t, with rank K X V, If is ^-transitive,we call the z^-socle of 11. If U is a primitve ring with r-socle , then we can find a pair of ^-modules (JT, whereJf3 is a subring of and we can define a dual topology in such that 11 is contained in the ring of all continuous endormorphisms of . We obtained an inclusion relation ?=S?(3ft, 2ft') 3J?7 j^') which refines the relation due to Jacobson: J§f(3ft, 2ft') iDllQ^o'133. We also proved that srf and are uniquely determined by 11 within semi-module isomorphism. In the last section, we obtained a structure theorem of finitely generated one-sided ideals of?,.