On Banach spaces X for which Π2 (X,L 1) = N1(X,L 1)

We prove that every 2-summing operator from a Banach space X into an L ₁-space is nuclear if and only if X is isomorphic to a Hilbert space. Then we study the class of Banach spaces X for which Π₂(l ₂, X) = N ₁(l ₂, X).     

Best Simultaneous Approximation in LΦ(I,X)

Let X be a Banach space and Φ be an Orlicz function.Denote by LΦ(I,X)the space of X-valued Φ-integrable functions on the unit interval I equipped with the Luxemburg norm.For f1,f2,...,fm ∈ LΦ(I,X),a distance formula disΦ(f1,f2,...,fm,LΦ(I,G))is presented,where G is a close subspace of X.Moreover,some existence and characterization results concerning the best simultaneous approximation of LΦ(I,G)in LΦ(I,X)are given.     

On Polarized 3-Folds (X,L) Such That <lowercase > h < /lowercase >0(L) = 2 and the Sectional Genus of (X,L) is Equal to the Irregularity of X

Let X be a smooth complex projective variety of dimension 3 and let L be an ample line bundle on X. In this article, we give a characterization of (X, L) with g(X, L) = q(X) and h⁰(L) = 2, where g(X, L) (resp. q(X)) denotes the sectional genus of (X, L) (resp. the irregularity of X).     

Weakly Sequential Completeness of L(l_p,X)and K(l_p,X)(1

《数学研究与评论》1992,(3)

赋Day范数的c0(Γ,X)的某些性质(英文)

设 Γ为一非空集 ,（ Ｘ ,ｙ ·ｙ） 为 Ｂａｎａｃｈ 空间． 本文主要结果 如下：（１） Ｕ（ｃ０ （Γ, Ｘ）,ｐ ） 为稳定 的当且仅当 Ｕ（ Ｘ） 是稳定的．（２） 设 Γ为无限集,那么下 列三条等价：（ａ） （ｃ０ （Γ, Ｘ ）,ｐ ） 有 λ性质 , （ｂ） （ｃ０ （Γ, Ｘ ）,ｐ ） 有一致 λ性质,（ｃ）（ Ｘ,ｙ ·ｙ） 有一致 λ性质 ．（３） 设 Γ为 有限集,那么（ｃ０ （Γ, Ｘ ）,ｐ ） 有 λ性 质（相应地,一致 λ性质） 当且 仅当（ Ｘ,ｙ ·ｙ） 有 λ性质（相应地,一致 λ性质）．（４） （ｃ０ （Γ, Ｘ）,ｐ ） 有 Ｋａｄｅｔｓ 性质 （相应地, Ｋａｄｅｔｓ Ｋｌｅｅ 性质） 当且仅 当（ Ｘ,ｙ ·ｙ） 有 Ｋａｄｅｔｓ 性质（相 应地, Ｋａｄｅｔｓ Ｋｌｅｅ 性质 ）．（５） ｗ ∈ Ｓ（ｃ０ （Γ, Ｘ）,ｐ ） 是 Ｕ（ｃ０ （Γ, Ｘ）,ｐ ） 的可凹点（相应 地, Ｐ Ｃ） 当且仅当对于 任意的 ｔ∈ Ｅ（ｗ ）,ｗ （ｔ） 是（ｘ ∈ Ｘ： ｙｘ ｙ ≤ ｙｗ （ｔ）ｙ） 的可凹点 （相应地, Ｐ Ｃ）．     

(L,M)-fuzzy闭包系统与(L,M)-fuzzy闭包算子

定义了(L,M)-fuzzy闭包系统与(L,M)-fuzzy闭包算子的概念,建立了给定集合X上(L,M)-fuzzy闭包系统的全体FCS(L,M,X)和(L,M)-fuzzy闭包算子的全体FCO(L,M,X)之间的一一对应(在此基础上证明了(L,M)-fuzzy闭包系统空间范畴LMFCSS与(L,M)-fuzzy闭包算子空间范畴LMFCOS是同构的)。此外还证明了(2,M)-fuzzy闭包系统空间范畴2MFCSS可嵌入到(L,M)-fuzzy闭包系统空间范畴LMFCSS,(2,M)-fuzzy闭包算子空间范畴2MFCOS可嵌入到(L,M)-fuzzy闭包算子空间范畴LMFCOS。     

L 1 (μ, X) as a constrained subspace of its bidual

In this note we consider the property of being constrained in the bidual, for the space of Bochner integrable functions. For a Banach spaceX having the Radon-Nikodym property and constrained in its bidual and forY ⊂ X, under a natural assumption onY, we show thatL ¹ (μ, X/Y) is constrained in its bidual andL ¹ (μ, Y) is a proximinal subspace ofL ¹(μ, X). As an application of these results, we show that, ifL ¹(μ, X) admits generalized centers for finite sets and ifY ⊂ X is reflexive, thenL ¹ μ, X/Y) also admits generalized centers for finite sets.     

Some Conditions for K_0(B(X))=0

Let A be an unital Banach algebra with the unital element I. We denote the set of (n×n)-matrices over A by Mn(A). The set of idempotent elements of A is denoted by P1(A):={P∈A: P2=P}, and accordingly the set of idempotent elements of Mn(A) is denoted by Pn(A):=P1(Mn(A)). We define P∞(A) :=∪n∈N Pn(A). In the set of P∞(A), for P,Q ∈ Pn(A), we say that P is (algebraic) equivalent to Q, if there exist A,B∈ Mn(A) such that     

О Тригонометрическом (0, 2)-Интерполировании

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(0,M)插值的推广

本文对周期为2ψ的函数引入了一类新的函数插值并建立了插值的收敛速度估计．通常的Birkhoff插值是该插值的极限情形．     

Unusual interactions of (1/2, 0) ⊕ (0, 1/2) particles

We continue to study the ‘fermion — 4-vector potential’ interactions in the framework of the McLennan-Case construct which is a reformulation of the Majorana theory of the neutrino. This theory is shown after applying Majorana-likeanzatzen to give rise to appearance of unusual terms as σ [A×A^*], which were recently discussed in non-linear optics.     

P型NFDE的(h_0,h,M_0)稳定性

本文将M0稳定性结合欢度量的概念推广到P型NFDE，并给出了稳定性的几个定理．     

二分(0,mf-m+1)-图的正交(0,f)-因子分解

设G=(X,Y,E(G))是一个二分图,分别用V(G)=XUY和E(G)表示G的顶点集和边集.设f是定义在V(G)上的整数值函数且对(A)x∈V(G)有f(x)≥k.设H_1,H_2,…,H_k是G的k个顶点不相交的子图,且|E(H_i)|=m,1≤i≤k.本文证明了每个二分(0,mf-m+1)-图G有一个(0,f)-因子分解正交于Hi(i=1,2,…,k).     

Small into-isomorphism from L∞ (A, μ) into L∞(B, υ)

In this paper we shall assert that if T is an isomorphism of L_∞(Ω₁, A, μ) into L_∞(Ω₂, B, υ) satisfying the condition ‖T‖·‖T ^?1‖?1+? for ?∈ $\left( {0,\frac{1}{5}} \right)$ , then $\frac{T}{{\parallel T\parallel }}$ is close to an isometry with an error less than 6ε in some conditions.     

Additional Note on Partial Regularity of Weak Solutions of the Navier-Stokes Equations in the Class L ∞(0, T, L 3(Ω)3)

We present a simplified proof of a theorem proved recently concerning the number of singular points of weak solutions to the Navier-Stokes equations. If a weak solution u belongs to L (0, T, L ³()³), then the set of all possible singular points of u in is at most finite at every time t₀ (0,T).     

Existence of weak solutions of 2-D Euler equations with initial vorticityω 0∈L(log+ L) α (α>0)

It is proved that there exist global weak solutions of 2-D Euler equations inR ² under the assumption that the initial vorticity belongs to a kind of wider spaces,L ¹L(log⁺ L) (>0), which are Orlicz spaces containing spacesL ^p L ¹,L(log⁺ L) L (>1/2) and so on. This result improves on that of [2], [4], [11]. Moreover, these solutions are obtained by vanishing the viscosity term of Navier-Stokes equations.     

f_(xy)(x_0,y_0)=f_(yx)(x_0,y_0)一个充分条件的介绍

一般高等数学教材中是这样给出二元函数二阶混合偏导数与求导次序无关的条件的：如果在点连续，则这个充分条件是可以减弱的，现介绍如下：定理如果在点（x。，y。）的某一邻域内，人（x，s）与人（x，，）都连续，且人（x，s）在（x。，y。）处连续，则几（x。，y。）存在，且人／X。，y）一九（X。，y）．证由偏导数的定义故只需证明（）、（2）两式右端之极限存在且相等。由于人（。，g）在（x。，g。）连续，从而由Lagrange中值定理有Q（｝1，足）一g（yo＋k）－g（yo）一kg’（yo＋0k），此处O＜「＜1．而／（y）一人（X。＋4，y）…