关于一类弱Berwald的(α,β)-度量

本文研究了一类重要的形如F=α +εβ +β arctan(β/α) (ε为常数)的弱Berwald (α, β)-度量.利用S-曲率公式,获得了这类度量为弱Berwald度量的充要条件.并且还证明了F为具有标量旗曲率的弱Berwald度量当且仅当它们为Berwald度量且旗曲率消失.     

(α,β)-γ开集与(α,β)-γ-Ti空间

本文首先给出(α,β)-γ开集定义,获得了(α,β)-γ开集性质;然后引入了(α,β)-γ-T_i空间和(α,β)-γ-T_i^*空间概念(i=0,1/2,1,2,5/2),并得到它们更广泛的拓扑性质.     

The Rν-generalized solution of a boundary value problem with a singularity belongs to the space W2,ν+β2+κ+1/κ+2 (Ω, δ)

In the present paper, for a boundary value problem with noncoordinated degeneration of the data and a singularity in the solution, we show that the R _ν -generalized solution belongs to the weighted space W _2,ν+gb ^2+κ+1/κ+2 (Ω, δ)(κ > 0). Original Russian Text ? V.A. Rukavishnikov, E.V. Kuznetsova, 2009, published in Differentsial’nye Uravneniya, 2009, Vol. 45, No. 6, pp. 894–898.     

一类α次殆β型螺形映照的偏差上界估计

本文研究了复向量空间Cn中开单位球Bn,复Banach空间中单位球B和域?p1,···,pn上一类α次殆β型螺形映照的偏差估计问题.利用不等式、矩阵及α次殆β型螺形映照的增长定理等方法,获得了上述域上的一类α次殆β型螺形映照的偏差上界估计,所得结果推广了一些已知的结论.     

Some projectively flat (α, β)-metrics

In this paper, we study a class of Finsler metrics in the form , where is a Riemannian metric, β = b _i y ⁱ is a 1-form, and ε and k ≠ 0 are constants. We obtain a sufficient and necessary condition for F to be locally projectively flat and give the non-trivial special solutions. Moreover, it is proved that such projectively flat Finsler metrics with the constant flag curvature must be locally Minkowskian.     

Spherical Harmonic Analysis on Buildings of Type ? n

 To any locally finite thick building of type there is naturally associated a commutative algebra of operators. When is constructed from a local field F with local ring , and , then is isomorphic to the convolution algebra of compactly supported bi-K-invariant functions on PGL(n+1,F). We give a proof, valid for any , that the multiplicative functionals on may all be expressed in terms of Hall–Littlewood polynomials. Regarding as a subalgebra of the C ^*-algebra of bounded operators on the space of square summable functions on the vertex set of , we find the spectrum of the C ^*-algebra , the closure of . This generalizes results obtained in [3] when n = 1 and in [5] when n = 2.     

Sum of sequence spaces and matrix transformations mapping in s α 0 ((Δ ? λ I ) h ) + s β ( c ) ((Δ ? μ I ) l )

We deal with the sum of sequence spaces. Then we apply these results to characterize matrix transformations mapping between s ^h,l (λ, μ) = s _α ⁰((Δ − λI) ^h ) + s _β ^(c)((Δ − μI) ^l ) and s _γ . Among other things the aim of this paper is to reduce the set (s ^h,l (λ, μ), s _γ to a set of the form S _τ,γ .      

Gaussian Estimates of Order α and L p -Spectral Independence of Generators of C 0-Semigroups

We prove L^p-spectral independence for generators of C₀-semigroups estimated by the positive C₀-semigroup . In the preliminary process of the proof, we obtain the asymptotic expansion formula for the integral kernel of the C₀-semigroup .     

The interior operation in a ψ -density topology

We prove that for an arbitrary setA ⊂ ℝ its interior in aψ-density topology equalsA ∩ φ^β(B), whereB is a measurable kernel ofA andβ is some countable ordinal. Moreover, eachβ, 1≤β<Ω, realizes the interior ofA for someA εS.     

(α,δ)-弱刚性环上的Ore扩张

本文研究（α,δ）-弱刚性环上的Ore扩张环R[x;α,δ]的弱对称性、弱zip性、幂零p.p.性和幂零Baer性.利用对多项式的逐项分析的方法,证明了如果R是（α,δ）-弱刚性环和半交换环,则Ore扩张环R[x;α,δ]是弱对称的（弱zip的,幂零p.p.的,幂零Baer的）当且仅当R是弱对称的（弱zip的,幂零p.p.的,幂零Baer的）.这些结果统一和扩展了前面已有的相关结论.     

Equivalence of Minimal ?0- and ?p-Norm Solutions of Linear Equalities, Inequalities and Linear Programs for Sufficiently Small p

For a bounded system of linear equalities and inequalities, we show that the NP-hard ℓ ₀-norm minimization problem is completely equivalent to the concave ℓ _p -norm minimization problem, for a sufficiently small p. A local solution to the latter problem can be easily obtained by solving a provably finite number of linear programs. Computational results frequently leading to a global solution of the ℓ ₀-minimization problem and often producing sparser solutions than the corresponding ℓ ₁-solution are given. A similar approach applies to finding minimal ℓ ₀-solutions of linear programs.     

Pairwise ?-independence of the sets TiA for a mixing transformation T

If an ergodic automorphism T of a probability space is not partially rigid, then for any numbers a ∈ (0, 1) and ɛ > 0 there exists a set A such that all sets T ⁱ A, i > 0, are pairwise ɛ-independent. __________ Translated from Funktsional’nyi Analiz i Ego Prilozheniya, Vol. 43, No. 2, pp. 88–91, 2009 Original Russian Text Copyright ? by V. V. Ryzhikov This research was carried out under the Program for Support of Leading Scientific Schools in the Russian Federation (grant no. 6849.2006.1).     

强β型螺形映照的增长和掩盖定理

本文研究了复Banach空间单位球上的强β型螺形映照.利用强β型螺形映照的定义及其几何特征,获得了复Banach空间单位球上强β型螺形映照的增长和掩盖定理,并结合k阶零点得到强β型螺形映照相应的增长和掩盖定理,推广了螺型映照的相应结论.     

The generalized bisymmetric solutions of the matrix equation A 1 X 1 B 1 + A 2 X 2 B 2 + ? + A l X l B l = C and its optimal approximation

For fixed generalized reflection matrix P, i.e. P ^T  = P, P ² = I, then matrix X is said to be generalized bisymmetric, if X = X ^T  = PXP. In this paper, an iterative method is constructed to find the generalized bisymmetric solutions of the matrix equation A ₁ X ₁ B ₁ + A ₂ X ₂ B ₂ + ⋯ + A _l X _l B _l  = C where [X ₁,X ₂, ⋯ ,X _l ] is real matrices group. By this iterative method, the solvability of the matrix equation can be judged automatically. When the matrix equation is consistent, for any initial generalized bisymmetric matrix group , a generalized bisymmetric solution group can be obtained within finite iteration steps in the absence of roundoff errors, and the least norm generalized bisymmetric solution group can be obtained by choosing a special kind of initial generalized bisymmetric matrix group. In addition, the optimal approximation generalized bisymmetric solution group to a given generalized bisymmetric matrix group in Frobenius norm can be obtained by finding the least norm generalized bisymmetric solution group of the new matrix equation , where . Given numerical examples show that the algorithm is efficient. Research supported by: (1) the National Natural Science Foundation of China (10571047) and (10771058), (2) Natural Science Foundation of Hunan Province (06JJ2053), (3) Scientific Research Fund of Hunan Provincial Education Department(06A017).     

Autour des formes quadratiques indécomposables de l’image de l’homomorphisme W(F) → W(F(φ))

Let F be a field of characteristic not 2. In this article, we treat the quadratic forms of Im(W(F) → W(F(φ))) which are indecomposable, i.e., those which are not isometric to a sum of two nonzero forms of this image, where W(F) is the Witt ring of F-quadratic forms, and F(φ) is the function field of the affine quadric given by φ. This is related to the descent problems studied in [12, 14]. More precisely, we will focus on indecomposable quadratic forms of minimal dimension, which we detail for φ of dimension less than or equal to 8. We also include other related results.     

On the Diophantine Equation G n ( x )?= G m ( P ( x ))

 Let K be a field of characteristic 0 and let p, q, G ₀ , G ₁ , P ∈K[x], deg P ⩾ 1. Further, let the sequence of polynomials (G _n (x)) _n=0 ^∞ be defined by the second order linear recurring sequence

On the Diophantine Equation G n ( x )?= G m ( P ( x ))

 Let K be a field of characteristic 0 and let p, q, G ₀ , G ₁ , P ∈K[x], deg P ⩾ 1. Further, let the sequence of polynomials (G _n (x)) _n=0 ^∞ be defined by the second order linear recurring sequence

Subexponential ultracontractivity and L p ? L q functional calculus

 We prove that if a symmetric submarkovian semigroup (T _t ) _t>0 satisfies an estimate of the form

球面稳定同伦群中第三周期γ类非平凡新元素

本文研究了球面稳定同伦群的问题.以Adams谱序列中的第二非平凡微分为几何输入,给出了球面稳定同伦群中h₀g_n（n > 3）的收敛性.同时,由Yoneda乘积的知识,发掘了球面稳定同伦群中的一个非平凡新元素.非平凡元素的范围将被我们的结果进一步扩大.     

On the description of overgroups of E(m,R)?E(n,R)

The subgroups E(m,R) ⊗ E(n,R) ≤ H ≤ G = GL(mn,R) are studied under the assumption that the ring R is commutative and m, n ≥ 3. The group GL _m ⊗GL _n is defined by equations, the normalizer of the group E(m,R) ⊗ E(n,R) is calculated, and with each intermediate subgroup H it is associated a uniquely determined lower level (A,B,C), where A,B,C are ideals in R such that mA,A ² ≤ B ≤ A and nA,A ² ≤ C ≤ A. The lower level specifies the largest elementary subgroup satisfying the condition E(m, n,R, A,B,C) ≤ H. The standard answer to this problem asserts that H is contained in the normalizer N _G (E(m,n,R, A,B,C)). Bibliography: 46 titles.