关于Ginsburg & Woods的一个问题

构造了一个反例回答了基数不等式|X|<2^c(X)Δ(X)不仅对于正则空间类不成立,甚至对Tychonoff空间类亦不成立。     

小区间中的整数的最大素因子

设ε>0,证明了:区间(X,X十X^1/2十ε]中存在这样一个整数,它有一个素因子P≥x^11/12-ε.     

关于某些拟一致空间的超空间拓扑

设(X,τ)是一个拓扑空间。在本文中,我们证明了在超空间2^X上局部有限拓扑e^τ与局部有限覆盖拟一致u_LF所导出的超拓扑|2^u_LF|是相同的。我们还证明了下面条件是等价的:(1)(X,τ)是仿紧的;(2)(X,τ)是orth紧的,且e^τ=|2^u_FT|;(3)存在一个Lebes-yue拟一致u_L,使e^τ<     

关于相邻素数之差

设B为充分大的正常数,ε为充分小的正常数,X和N充分大.主要证明了:1)对于正整数n,X<n≤2X,除去O(Xlog^-BX)个例外值,区间(n,n+n^1/14+ε)中包含一个素数;2)如果A+N^1/12+ε,则区间(N,N+A)中的偶数,除去O(Alog^-BN)个例外值,均匀Goldbach数.     

简单自反DTS(ν,λ)的存在谱

一个Directed三元系DTS(ν,λ)=(X,B)是自反的,如果它与它的逆(X,B^-1)同构,其中B^-1={(z,y,x);(x,y,z)∈B}.继已给出SCDTS(ν,λ)的存在谱之后,又给出简单SCDTS(ν,λ)的存在谱.     

赋范线性空间中包含方程可解性定理的推广及弱切锥的应用

本文首先在一般的赋范线性空间中研究了集值映射F;X→Y的平衡点的存在性问题,证明了包含问题O∈F(X)的三个可解性定理.然后在无穷维空间中研究了弱相依锥T_k^σ(x)的直接像,弱相依导数D^σF(x,y)的一个链式法则以及偏y弱导数D_y^σF(x,y)的弱Lip连续性.最后,作为应用,给出并证明了用弱相依导数D^σF(x,y)及弱P导数P^σF(x,y)判定无穷维     

齐型空间上带非光滑核的奇异积分算子的双权不等式

该文在齐型空间( X, d,μ)上建立带非光滑核的奇异积分算子的双权、弱型不等式, 即对于1< p≤ q <∞, 此算子是L^p( X, v)到 L^q,∞( X, u)有界的, 只要权函数对(u, v)满足在权 u 上增加一个"Orlicz-bump" '的 A_p 型条件.     

Banach空间上有界线性算子的Drazin逆的扰动分析

设X为一复域C上的Banach空间,设T:X→X为一有界线性算子,其指标为k且R(T^k)闭.记T的Drazin逆为T^D.设T=T+δT,则在一定条件下,T^D有简明分解式T^D=T^D(I+δTT^D)^-1=(I+T^DδT)^-1T^D,从而导出了相对误差‖T^D-T^D<     

(l,l,…,l)型数域

设K~n是Abel数域,Gal(Kⁿ/Q)≌(Z/lZ)ⁿ。本文对一般素数l,一般n刻画了Kⁿ的结构。特别是完全解决了Kⁿ的判别式密度问题,即明显给出ⅰ)Kⁿ的判别式。ⅱ)判别式为D的Kⁿ的个数J(D)。ⅲ)判别式小于X的Kⁿ的个数N(X)～,C是明显给出常数(l=2情形引作者另文)。Hasse,Cohn,Baily等的结果作为特殊情形含于本文结果之中。     

齐型空间上的BMO函数

本文初等而又简单地证明了如下事实。设f是齐型空间X上函数,使这里k∈Z⁺,(log⁺)^k是k次对数重叠,S遍历X中所有的球,则f∈BMO。并且因此建立了Baernstein定理在n维实、复球上的一个类似。     

On cardinality bounds involving the weak Lindelöf degree

We give a general closing-off argument in Theorem 2.3 from which several corollaries follow, including (1) if X is a locally compact Hausdorff space then |X| ≤ 2^wL(X)ψ(X), and (2) if X is a locally compact power homogeneous Hausdorff space then |X| ≤ 2^wL(X)t(X). The first extends the well-known cardinality bound 2^ψ(X) for a compactum X in a new direction. As |X| ≤ 2^wL(X)χ(X) for a normal spaceX[4], this enlarges the class of known Tychonoff spaces for which this bound holds. In 2.12 we give a short, direct proof of (1) that does not use 2.3. Yet 2.3 is broad enough to establish results much more general than (1), such as if X is a regular space with a π-base ? such that |B| ≤ 2^wL(X)χ(X) for all B ∈ ?, then |X| ≤ 2^wL(X)χ(X).

Separately, it is shown that if X is a regular space with a π-base whose elements have compact closure, then |X| ≤ 2^{wL(X)ψ(X)t(X)}. This partially answers a question from [4] and gives a third, separate proof of (1). We also show that if X is a weakly Lindelöf, normal, sequential space with χ(X) ≤ 2^?0, then |X| ≤ 2^?0.

Result (2) above is a new generalization of the cardinality bound 2^t(X) for a power homogeneous compactum X (Arhangel'skii, van Mill, and Ridderbos [3], De la Vega in the homogeneous case [10]). To this end we show that if U ? clD ? X, where X is power homogeneous and U is open, then |U| ≤ |D|^πχ(X). This is a strengthening of a result of Ridderbos [19].     

Some new Triebel-Lizorkin spaces on spaces of homogeneous type and their frame characterizations

Let(X,p,μ)d,θ be a space of homogeneous type,(?) ∈(0,θ],|s|＜(?) andmax{d/(d＋(?)),d/(d＋s＋(?))}＜q≤∞.The author introduces the new Triebel-Lizorkin spaces (?)_∞q~s(X) and establishes the framecharacterizations of these spaces by first establishing a Plancherel-P(?)lya-type inequalityrelated to the norm of the spaces (?)_∞q~s(X).The frame characterizations of the Besovspace (?)_pq~s(X) with|s|＜(?),max{d/(d＋(?)),d/(d＋s＋(?))}＜p≤∞ and 0＜q≤∞and the Triebel-Lizorkin space (?)_pq~s(X)with|s|＜(?),max{d/(d＋(?)),d/(d＋s＋(?))}＜p＜∞ and max{d/(d＋(?)),d/(d＋s＋(?))}＜q≤∞ are also presented.Moreover,the au-thor introduces the new TriebeI-Lizorkin spaces b(?)_∞q~s(X) and H(?)_∞q~s(X) associated to agiven para-accretive function b.The relation between the space b(?)_∞q~s(X) and the spaceH(?)_∞q~s(X) is also presented.The author further proves that if s＝0 and q＝2,thenH(?)_∞q~s(X)＝(?)_∞q~s(X),which also gives a new characterization of the space BMO(X),since (?)_∞q~s(X)＝BMO(X).     

On Reproducing Kernel Hilbert Spaces of Polynomials

Let (X,Y) be a minimal compactifiurtion of ?². In this paper, we determine the structure of such a (X,Y) in the case where X is a normal hypersurface of degree d ≤ 4 in P³.     

Clan acts and codimension

Let (T, X) be a continuum act, let cd X=n and suppose A is a T-ideal (i.e., a T-invariant subspace of X), such that Hⁿ(A)≠0. We prove that A is a minimal T-ideal iff A=Gx for some x∈X and maximal group G in the minimal ideal of T. Moreover, if these conditions are satisfied, then A is the only minimal T-ideal and also is the unique floor for every nonzero element of Hⁿ(X). We need and also prove here an improved version of the Tube Theorem [3], and this corollary: if (G, X) is an intransitive transformation group with G compact, X locally compact and finite dimensional, and X/G connected, then dimension Gx<dimension X for all x∈X. NSF GP 9659. NSF GP 28655.     

On the chow group and the intermediate jacobian of a conic bundle

Sunto In questo lavoro si studiano fibrati in coniche X su una superficie non singolare S. I fibrati in coniche si presentano nella classificazione delle varietà algebriche a tre dimensioni aventi dimensione di Kodaria negativa. Si descrivono qui, a meno di isogenie, il gruppo A²(X) dei cicli di codimensione due algebrieamente equivalenti a zero e la iacobiana intermedia J(X). Quando S è una superficie razionale, A²(X) e J(X) vengono descritti a meno di isomorfismi ottenendo risultati già provati da Beauville nel caso S=P ².     

Union of linear spaces in infinite-dimensional projective spaces and holomorphic vector bundles

Let V be a localizing Banach space with an unconditional countable basis, X an equicodimensional transversal union of finite-codimensional linear subspaces of P(V) and E a holomorphic vector bundle of finite rank on X. Here we prove that Hⁱ(X,E) = 0 for every i > 0 and that E is isomorphic to a direct sum of line bundles ^OX(t).     

Factorization of mappings of topological spaces and homomorphisms of topological groups in accordance with weight and dimension ind

Symbols w(X), nw(X), and hl(X) denote the weight, the network weight, and the hereditary Lindelöf number of a space X, respectively. We prove the following factorization theorems.

1. Let X and Y be Tychonoff spaces, φ: X→Y a continuous mapping, hl(X)≤τ, and w(Y)≤τ. Then there exist a Tychonoff space Z and continuous mappings ψ: X→Z, χ: Z→Y such that φ=χ o ψ, Z=ψ(X), w(Z)≤τ andind Z≤ind X. Moreover, if nw(X)≤τ, then mapping ψ is one-to-one.
2. Let π: G→H be a continuous homomorphism of a Hausdorff topological group G to a Hausdorff topological group H, hl(G)≤τ and w(H)≤τ. Then there are a Hausdorff topological group G^* and continuous homomorphisms g: G→G^*, h: G^*→H so that π=h o g, G^*=g(G), w(G^*)≤τ andind G^*≤ind G. If nw(G)≤τ, then g is one-to-one.
3. For every continuous mapping φ: X→Y of a regular Lindelöf space X to a Tychonoff space Y one can find a Tychonoff space Z and continuous mappings ψ: X→Z, χ: Z→Y such that φ=χ o ψ, Z=ψ(X), w(Z)≤w(Y),dim Z≤dim X, andind ₀ Z≤ind ₀ X, whereind ₀ is the dimension function defined by V.V.Filippov with the help of G_δ-partitions. If we additionally suppose that X has a countable network, then ψ can be chosen to be one-to-one. The analogous result also holds for topological groups.
4. For each continuous homomorphism π: G→H of a Hausdorff Lindelöf Σ-group G (in particular, of a σ-compact group G) to a Hausdorff group H there exist a Hausdorff group G^* and continuous homomorphisms g: G→G^*, h:G^*→H so that π=h o g, G^*=g(G), w(G^*)≤w(H),dimG^*≤dimG, andind G^*≤ind G. Bibliography: 25 titles.

     

On Polarized Surfaces (X, L) with h0(L) > 0, κ(X) ≥ 0 and g(L) = q(X) + 1

Let (X,L) be a polarized surface. If h⁰(L)>0, then g(L) q(X). In our previous papers, we classified polarized surfaces (X,L) with g(L)=q(X) and h⁰(L)>0. In this paper, we classify polarized surfaces (X,L) with g(L)=q(X)+1, h⁰(L)>0, and (X) 0.     

GENERALIZED CLIFFORD TORUS IN S~(n+1)AND PRESCRIBED MEAN CURVATURE FUNCTION

Given some function H(X),one can find a compact hypersurface in S~(n+1),which ishomeomorphic to S~m(1)×S~(n-m)(1)and whose mean curvature is given by H(X).     

Commutators of BMO functions and singular integral operators with non-smooth kernels on spaces of Homogeneous type of finite measure

Let X be a space of homogeneous type with finite measure. Let T be a singular integral operator which is bounded on Lp (X), 1 ＜ p ＜∞. We give a sufficient condition on the kernel k(x,y) of Tso that when a function b ∈ BMO (X) ,the commutator [b, T] (f) = T (b f) - bT (f) is aounded on spaces Lp for all p, 1 ＜ p ＜∞.