关于Mori整环的$w$-全局变换环的注记

Let R be a domain and let Rwg be the w-global transform of R. In this note it is shown that if R is a Mori domain, then the t-dimension formula t-dim（Rwg） = t-dim（R） - 1 holds.     

A Note on the ω-Global Transform of Mori Domains

Let R be a domain and let Rωg be the ω-global transform of R. In this note it is shown that if R is a Mori domain, then the t-dimension formula t- dim(Rωg) = t-dim(R)-1 holds.     

An Upper Bound for the w-Weak Global Dimension of Pullbacks

Let R be a commutative ring with identity and I0 an ideal of R.We introduce and study the c-weak global dimension c-w.gl.dim(R/I0) of the factor ring R/I0.Let T be a w-linked extension of R,and we also introduce the wR-weak global dimension wR-w.gl.dim(T) of T.We show that the ring T with wR-w.gl.dim(T) =0 is exactly a field and the ring T with wR-w.gl.dim(T) ≤ 1 is exactly a PwRMD.As an application,we give an upper bound for the w-weak global dimension of a Cartesian square (RDTF,M).More precisely,if T is w-linked over R,then w-w.gl.dim(R) ≤ max{wR-w.gl.dim(T) + w-fdR T,c-w.gl.dim(D) + w-fdn D}.Furthermore,for a Milnor square (RDTF,M),we obtain w-w.gl.dim(R) ≤ max{wR-w.gl.dim(T) + w-fdR T,w-w.gl.dim(D) + w-fdR D}.     

一类弱整体维数为2的局部环上的Bass-Quillen问题II

设R是U2环,即(R,m)是局部GCD整环,且存在u∈m-m2,使得R/(u)是赋值环,且Ru是Bézout整环.本文证明了若R是带有正规元素为u的U2环,且dim(R/(u))=1,则每个有限生成投射R[X1,...,Xn]模是自由模.由此得到了若R是广义伞环,则每个有限生成投射R[X1,...,Xn]模是自由模.     

Remarks on pseudo-valuation rings

A prime ideal P of a ring A is said to be a strongly prime ideal if aP and bA are comparable for all a,b ε A. We shall say that a ring A is a pseudo-valuation ring (PVR) if each prime ideal of A is a strongly prime ideal. We show that if A is a PVR with maximal ideal M, then every overring of A is a PVR if and only if M is a maximal ideal of every overring of M that does not contain the reciprocal’of any element of M.We show that if R is an atomic domain and a PVD, then dim(R) ≤ 1. We show that if R is a PVD and a prime ideal of R is finitely generated, then every overring of R is a PVD. We give a characterization of an atomic PVD in terms of the concept of half-factorial domain.     

广义时滞Hopfield型神经网络系统的平稳周期振荡

本文利用重合度理论和 V-泛函研究了一类具有周期输入的广义时滞 Hopfield型连续神经网络系统的平稳周期振荡问题 ,得到了其周期解存在、唯一和全局吸引的充分条件 .     

二阶拟线性中立型时滞微分方程的振动性

考虑二阶中立型时滞微分方程[a(t)|(x(t) p(t)x(t-τ)）′|^α-1(x(t) p(t)x(t-τ））′]′ f(t,x(t-σ））=0(E)其中α，τ，σ是非负常数，a(t),p(t)∈C([t0,∞），R），f(t,x)∈C(R,R)。建立了方程（E）的一些新的振动条件。     

Goldie dimension of a sum of modules

The formula dim(A+B)=dim(A)+dim(B)-dim(A∩B) works when ‘dim’ stands for the dimension of subspaces A,B of any vector space. In general, however, it does no longer hold if 'dim' means the uniform (or Goldie) dimension of submodules A,B of a module M over a ring R, and in fact the left hand side may be infinite while the right hand side is finite. In this paper we shall give a characterization of those modules M in which the formula holds for any two submodules A,B, as well as some conditions in the ring R which guarantee that dim(A+B) is finite whenever A and B are finite dimensional R-modules.     

一类带有时滞的偏微分方程的振动性

研究中立型时滞微分方程     

On Bounded Positive(m,p)-Circle Domains

Let D be a bounded positive(m, p)-circle domain in C~2. The authors prove that if dim(Iso(D)~0) = 2, then D is holomorphically equivalent to a Reinhardt domain; if dim(Iso(D)~0) = 4, then D is holomorphically equivalent to the unit ball in C~2. Moreover,the authors prove the Thullen's classification on bounded Reinhardt domains in C~2 by the Lie group technique.     

两类整环在w-算子下的刻画

通过对SM整环中准素w-理想与w-互素理想的讨论,证明了R是Krull整环当且仅当R是SM整环,w-dim(R)=1,且每个p-准素w-理想是素理想p的幂的w-包络.同时,运用w-算子,辅以t-,v-算子给出了π-整环的一些新的等价刻画.     

关于w-linked扩环

Let R ■ T be an extension of commutative rings.T is called w-linked over R if T as an R-module is a w-module.In the case of R ■ T ■ Q 0 （R）,T is called a w-linked overring of R.As a generalization of Wang-McCsland-Park-Chang Theorem,we show that if R is a reduced ring,then R is a w-Noetherian ring with w-dim（R） 1 if and only if each w-linked overring T of R is a w-Noetherian ring with w-dim（T ） 1.In particular,R is a w-Noetherian ring with w-dim（R） = 0 if and only if R is an Artinian ring.     

关于一个二阶非线性中立时滞微分方程的非振荡解的存在性

A new second-order nonlinear neutral delay differential equation r（t） x（t） ＋ P（t）x（t-τ） ＋ cr（t） x（t）-x（t-τ） ＋ F t,x（t-σ1）,x（t-σ2）,...,x（t-σn） = G（t）,t ≥ t0,where τ 0,σ1,σ2,...,σn ≥ 0,P,r ∈ C（[t0,＋∞）,R）,F ∈ C（[t0,＋∞）×Rn,R）,G ∈ C（[t0,＋∞）,R） and c is a constant,is studied in this paper,and some sufficient conditions for existence of nonoscillatory solutions for this equation are established and expatiated through five theorems according to the range of value of function P（t）.Two examples are presented to illustrate that our works are proper generalizations of the other corresponding results.Furthermore,our results omit the restriction of Q1（t） dominating Q2（t）（See condition C in the text）.     

On the Equivariant Tamagawa number conjecture for Tate motives

Let L be a finite abelian extension of and let K be any subfield of L. For each integer r with r0 we prove the Equivariant Tamagawa Number Conjecture for the pair (h⁰(Spec(L))(r),[&frac;][Gal(L/K)]). Mathematics Subject Classification (1991) 11G40, 11R23, 11R33, 11R65     

Äussere Potenzen von Differentialmoduln Reduzierter Vollständiger Durchschnitte

Let R be an analytic algebra over the perfect field k. Assume that R is a reduced complete intersection. Then the i-th exterior powers of the KäHLER differential module of R over k are torsionfree (resp. reflexive) for i=1,...,p if and only if the codimension of the singular locus of R is greater than inf{p,dim R} (resp. inf{p+1,dim R}).

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Bei der vorliegenden Arbeit handelt es sich um einen Teil der Habilitationsschrift des Verfassers.     

关于《关于Ramsey数下界的部分结果》的注

本文用反例 ,说明了 [1 ]中 R( l,s+ t-2 ) R( l,s) + R( l,t) -1是错的     

ASYMPTOTIC STABILITY FOR A CLASS OF NONAUTONOMOUS NEUTRAL DIFFERENTIAL EQUATIONS

ＡＳＹＭＰＴＯＴＩＣＳＴＡＢＩＬＩＴＹＦＯＲＡＣＬＡＳＳＯＦＮＯＮＡＵＴＯＮＯＭＯＵＳＮＥＵＴＲＡＬＤＩＦＦＥＲＥＮＴＩＡＬＥＱＵＡＴＩＯＮＳ＊＊ＹＵＪＩＡＮＳＨＥ＊ＭａｎｕｓｃｒｉｐｔｒｅｃｅｉｖｅｄＪｕｌｙ４，１９９５．ＲｅｖｉｓｅｄＭａｒｃｈ２...     

一类中立型时滞抛物偏微分方程的强迫振动性

研究了一类中立型时滞抛物偏微分方程:t(u(x,t)-pu(x,t-τ))-∑rk=1ak(t)Δu(x,t-ρk(t))+∑mj=1qj(t)u(x,t-σj(t))=e(x,t),的强迫振动性(其中(x,t)∈Ω×[0,∞)≡G,Ω是n维欧几里得空间Rn中带有逐段光滑边界Ω的有界区域,Δ是Rn中带有三类不同边值条件的拉普拉斯算子,强迫项e(x,t)是定义在G上的一个振荡函数),给出了一些新的振动性判据,这些结果推广了已知的一些结论.     

Control subspaces of minimal dimension and root vectors

We investigate the following characteristic of a linear operator A in a Banach space X: disc {inf(dim R′:R′?R,R′εCyc A) :RεCyc A}, where Cyc A={R:R is a subspace of X, dim R<∞, span (AⁿR: :n≥0)=X}. The value disc A is equal to the dimension of a cyclic subspace that can be chosen in an arbitrary cyclic finite dimensional subspace. If we consider a dynamical system \(\dot x = Ax + Bu\) with the controllability property, disc A shows to what extent the dimension of the input subspace of control can be diminished without loss of controllability. In this paper we investigate when easy inequality disc A≥(the multiplicity of A) turn into the equality. Some estimates from below of disc A (of the type disc A≥sup dim Ker(A-λI)) are found for some classes of operators e.q. for compact operators, for Toeplitz operators with antianalytic symbols, for strictly lower triangular operators and some other classes.     

Uniform distribution of integral points on multidimensional ellipsoids

Let Q(X), X^T=(x₁,...,x_l), be a positive definite, integral-valued, primitive, quadratic form of l4 variables, let () be the number of solutions of Eq. Q(X)=n, let (,) be the number of the solution of the equation Q(X)=n such that X/, where is an arbitrary convex domain on Q(X)=1 with a piecewise smooth boundary. One investigates the asymptotic behavior of the quantity (,) (n). In the case of an even l4 the result is formulated in the following manner: for (n,N)=1 and n one has, >o, where() is the measure of the domain , normalized by the condition(E)=1, where E is the ellipsoid Q(X)=1. Weaker results have been obtained earlier by various authors. In the case of the simplest domains (belt, cap) the remainder in (1) can be brought to the form. The last estimate for large l is close to an unimprovable one. The proof makes use of the theory of modular forms and of Deligne's estimates.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 154, pp. 144–153, 1986.