Pseudo-contractibility of chainable continua

A space X is called pseudo-contractible if there exist a mapping and points a,b∈C, x₀∈X, where C is a continuum, fulfilling H(x,a)=x and H(x,b)=x₀. We show that the only (up to homeomorphism) pseudo-contractible chainable continuum is the arc. In particular the pseudo-arc is not pseudo-contractible, which answers a question of W. Kuperberg.     

Numerical recipes for the high efficient inverse of the confluent Vandermonde matrices

In this paper, we derive a numerical recipe for the calculation of the inversion of the confluent Vandermonde matrix. The main result of this article does not require any symbolic calculations and therefore can be performed by a numerical algorithm implemented either in any high level (like Matlab or Mathematica) or low level programming language (C/C++/Java/Pascal/Fortran, etc.). The computational complexity of the presented algorithm is of an O(N²) class being, by the linear term, better than the ordinary Gauss elimination method. Moreover, a ready to use C++ full implementation of the algorithm is attached.     

Property A for groups acting on metric spaces

Gouliang Yu has introduced a property of discrete metric spaces and groups called property A which implies the coarse Baum–Connes Conjecture and hence the Novikov Higher Signature Conjecture. In this paper we extend a result of Jean-Louis Tu to conclude that a group acting by isometries on a metric space with finite asymptotic dimension whose d-stabilizers have property A, also has property A. As a result, we conclude a theorem of Tu, according to which, a fundamental group of a finite graph of groups whose vertices have property A also has property A.     

Property T＊＊ for C＊-algebras

Extending the notion of property T of finite von Neumann algebras to general von Neumann algebras, we define and study in this paper property T** for (possibly non-unital) C* -algebras. We obtain several results of property T** parallel to those of property T for unital C* -algebras. Moreover, we show that a discrete group Γ has property T if and only if the group C* -algebra Cr* (Γ) (or equivalently, the reduced group C* -algebra Cr* (Γ)) has property T**. We also show that the compact operators K(l2 ) has property T** but c0 does not have property T**.     

有界线性算子的性质(gy)

定义了四种新的谱性质:性质(y),性质(gy),性质(by),性质(gby),从而再次推广了Weyl型定理,并探讨了这四种新性质同Weyl型定理及其推广性质之间的关系.     

The Single Valued Extension Property for Operator Weighted Shifts

ＴｈｅＳｉｎｇｌｅＶａｌｕｅｄＥｘｔｅｎｓｉｏｎＰｒｏｐｅｒｔｙｆｏｒＯｐｅｒａｔｏｒＷｅｉｇｈｔｅｄＳｈｉｆｔｓＬｉＪｕｅｘｉａｎ（李觉先）（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｈｅｍａｔｉｃｓ，ＬｉａｏｎｉｎｇＵｎｉｖｅｒｓｉｔｙ，Ｓｈｅｎｙａｎｇ，１...     

A New Characterization of the Analytic Radon-Nikodym Property for Bounded S

ＡＮｅｗＣｈａｒａｃｔｅｒｉｚａｔｉｏｎｏｆｔｈｅＡｎａｌｙｔｉｃＲａｄｏｎ－ＮｉｋｏｄｙｍＰｒｏｐｅｒｔｙｆｏｒＢｏｕｎｄｅｄＳｕｂｓｅｔｓＢｕＳｈａｎｇｑｕａｎ（步尚全）（ＤｅｐａｒｔｍｅｎｔｏｆＡｐｐｌｉｅｄＭａｔｈｅｍａｔｉｃｓ，Ｔｓｉｎｇｈ...     

Lemniscates and inequalities for the logarithmic capacities of continua

It is shown that if P(z) = z ⁿ + ? is a polynomial with connected lemniscate E(P) = {z: ¦P(z)¦ ≤ 1} and m critical points, then, for any n? m+1 points on the lemniscate E(P), there exists a continuum γ ? E(P) of logarithmic capacity cap γ ≤ 2^?1/n which contains these points and all zeros and critical points of the polynomial. As corollaries, estimates for continua of minimum capacity containing given points are obtained.     

The Alternative Dunford–Pettis Property for Subspaces of the Compact Operators

A Banach space X has the alternative Dunford–Pettis property if for every weakly convergent sequences (x_n) → x in X and (x_n*) → 0 in X* with ||x_n|| = ||x||= 1 we have (x_n*(x_n)) → 0. We get a characterization of certain operator spaces having the alternative Dunford–Pettis property. As a consequence of this result, if H is a Hilbert space we show that a closed subspace M of the compact operators on H has the alternative Dunford–Pettis property if, and only if, for any h ∈ H, the evaluation operators from M to H given by S ↦ Sh, S ↦ S^th are DP1 operators, that is, they apply weakly convergent sequences in the unit sphere whose limits are also in the unit sphere into norm convergent sequences. We also prove a characterization of certain closed subalgebras of K(H) having the alternative Dunford-Pettis property by assuming that the multiplication operators are DP1.     

Contact Dehn surgery, symplectic fillings, and Property P for knots

These are notes of a talk given at the Mathematische Arbeitstagung 2005 in Bonn. Following ideas of Özbağcı–Stipsicz, a proof based on contact Dehn surgery is given of Eliashberg's concave filling theorem for contact 3-manifolds. The role of the theorem in the Kronheimer–Mrowka proof of Property P for nontrivial knots is sketched.     

Sums of products of hypergeometric Bernoulli numbers

We give a formula for sums of products of hypergeometric Bernoulli numbers. This formula is proved by using special values of multiple analogues of hypergeometric zeta functions.     

A Reproductive Property for a Class of Non-Newtonian Fluids

In this work we analyse a class of non-Newtonian reproductive fluid with a non-linear viscosity. The latter follows the power law or the Carreau's laws which is in common use for polymeric fluids. For a generalized data we introduce some special estimates and then obtain an existence result for the reproductive flow according to certain values of parameters appearing in the model.     

A stochastic algorithm for optimization problems with continua of inequalities

Optimization algorithms for solving mathematical programming problems involving continua of inequalities are presented. The algorithms use an outer-approximation method, by which they attempt to approximate, at each point, the maxima of sets of inequality constraints. They do so by performing random experiments, resulting in a finite number of points, over which the maximum is taken. They use constraint-dropping schemes, by which they eliminate points from the constraint set at hand, which are felt to be irrelevant. At each point that the algorithms construct, they evaluate a measure of optimality, which indicates the distance of the point from the set of solutions of the optimization problem. They use this measure to determine the number of random experiments performed. Thus, the number of such experiments tends to be small initially, when the points at hand are far from optimal, and they tend to increase when an optimal point is approached.     

完全分配格的内蕴式刻划与性质P

本文基于Ｒａｎｅｙ的内蕴式刻划定理对偏序集引入了性质Ｐ，讨论了性质Ｐ与余素元、紧元和强紧元诸概念之间的关系，证明了链具有性质Ｐ，作为其推论知完备链为完全分配格。     

Homological Characterizations of Rings with Property (P)

Abstract

A commutative ring R is said to satisfy property (P) if every finitely generated proper ideal of R admits a non-zero annihilator. In this paper we give some necessary and sufficient conditions that a ring satisfies property (P). In particular, we characterize coherent rings, noetherian rings and Π-coherent rings with property (P).     

Extension theorems for some classes of continua

It is proved that every mapping from a proper subcontinuum of a hereditarily unicoherent continuum X onto the Knaster's indecomposable continuum (onto a cone over a zerodimensional compact metric set) can be extended to a mapping defined on X.Similarly, every mapping from a proper subcontinuum of a hereditarily indecomposable continuum onto a pseudoarc can be extended to a mapping defined on the whole space.Both of the above results are generalizations of the author's earlier results to the nonmetric case. As a consequence it is obtained that a pseudoarc is continuously n-homogeneous.     

自反Banach空间中非扩张映像的强收敛定理

在Banach空间框架下考虑了一个关于无限族非扩张映射的一般迭代方法,此结论改进和推广了他人的许多结论.     

Topological properties of asymptotically stable sets

Topological properties of the domain of attraction for dynamical systems are investigated. The main purpose of this paper is to prove that a compact, asymptotically stable attractor of a dynamical system defined on a locally compact metric space is a deformation retract of its domain of attraction, in a weak sense that is made precise. Under additional local assumptions, the attractor can be shown to be a retract, a deformation retract, or a strong deformation retract. The well known result that the domain of attraction of an asymptotically stable equilibrium is contractible follows as a corollary.     

On Banach spaces with Kasparov and Yu's Property (H)

A new geometric property of Banach spaces recently introduced by G. Kasparov and G. Yu, called Property (H), has important applications to the strong Novikov conjecture and the coarse Novikov conjecture, yet is far from being well understood. In this paper, we investigate various uniformly continuous maps on unit spheres of Banach spaces and prove that all separable Banach lattices with nontrivial cotype have Property (H).