再谈关于C^∞—字幂的一个猜想

设Ｗ是一个Ｃ＾∞－字，且│Ｗ│〉３，若对一切满足│Ｄ＾ｋ（Ｗ）│〉１的自然数ｋ，都有Ｄ＾ｋ（Ｗ）的首末两个循环中至少有一个循环的长为２，则称Ｗ是一个弱偶Ｃ＾∞－字，本文讨论了弱偶Ｃ＾∞－字的性质，证明了以下的结论；基Ｗ是一个弱偶Ｃ＾∞－字，则Ｗ６２不是Ｃ＾∞－字。     

弱Herz空间的应用

设１〈ｑ〈∞和０〈ｐ≤１，本文证明了一大类算子有界地映Ｈｅｒｚ空间Ｋｑ＾ｎ（１－１／ｑ，＾ｐ（Ｒ＾ｎ）到弱Ｈｅｒｚ空间ＷＫｑ＾ｎ（１－１／ｑ），＾ｐ（Ｒ＾ｎ）。本文还引入了弱Ｈｅｒｚ型Ｈａｒｄｙ空间，并且证明了局部Ｃａｌｄｅｒｏｎ－Ｚｙｇｍｕｎｄ型算子有界地映Ｈｅｒｚ型Ｈａｒｄｙ空间到弱Ｈｅｒｚ型Ｈａｒｄｙ空间。     

Box－样条曲面的正性条件

研究了Ｂｏｘ－样条曲面的控制点与Ｂｏｘ－样条曲面的正性之间的关系．给出了Ｂｏｘ－样条曲面正性的必要条件、充分条件．由此我们得到了Ｂｏｘ－样条曲面的单调性条件，推广了Ｗ．ＤＡＨＭＥＮ和Ｃ．Ａ．ＭＩＣＣＨＥＬＬＩ在文［２］中给出的Ｂｏｘ－样条曲面的单调性结论     

CO—s闭拓扑

本文证明，当空间赋予ＣＯ－ｓ－闭石扑ｓ（τ）时，ｓ－连续函数概念与连续函数概念一致，研究了ｓ－ｘ闭空间；ｓ－闭空间的某些基本性质，且用其刻画几类ＣＯ－ｓ闭拓扑。     

半鞅及其临界停时

本文讨论Ｂ－值Ｒ．Ｒ．Ｃ过程Ｗ的半鞅性及其与临界停时之间的关系，同时给出相应的临界停时的构作方法，并证明过程Ｗ为非半鞅的特征为Ｐ（＜∞）＞０．本文最后讨论两类矢值过程，它们具有一个Ｒ－控制过程，但不为半鞅．     

一般正则泛函的W-极小的正则性

本文讨论了一般的正则泛函：Ｆ（ｕ；Ω）＝∫_{Ωｆ（ｘ，ｕ，Ｄｕ）ｄｘ的局部Ｗ－极小的Ｃ^１，α正则性．获得了处理Ｗ－极小ｕ的Ｈ?ｌｄｅｒ连续的指数估计．}     

广义a-结合BCI-代数

引入了广义ａ－结合ＢＣＩ－代数的概念，研究了ＢＣＩ－代数的ｐ－半单部分与广义ａ－结合部分的关系．并将ｐ－半单ＢＣＩ－代数的若干重要性质推广到广义ａ－结合ＢＣＩ－代数上．最后我们证明了每个广义ａ－结合ＢＣＩ－代数可确定一个交换偏序幺半群．本文结果表明文［１］的正则ＢＣＩ－代数与ｐ－半单ＢＣＩ－代数是一致的．     

α-方程的C_(p,q)~(k α)-形式解及其上确界范数估计

文中研究了－－方程在拟凸域上的积分解算子的性质，得到了－－方程在具Ｃｋ（ｋ≥０）类边界的拟凸开集上的Ｃｋ＋αｐ，ｑ－形式的积分算子解及其解的上确界范数估计，它包含了文［１］仅对Ｃ∞的情形     

C~n空间中Cauchy-Fantappiè公式的另一种形式

本文得到Ｇｎ空间中有界域上全纯函数的一种抽象的积分公式；这个公式的特点是积分核含有向量函数Ｗ，又含有Ｄ上任意ｎ－１个固定点，而积分密度函数含有全纯函数的导数，它可以看成是有界域上Ｃａｕｃｈｙ－Ｆａｎｔａｐｐｉｅ公式的另一种形式；利用这个公式；通过适当选择其中的向量函数，可以得到许多区域上全纯函数相应的积分表示式．     

Toeplitz算子空间的W—闭包

本文讨论了Ｔｏｅｐｌｉｔｚ算子空间的Ｗ－闭包，我们证明了Ｂｅｒｇｍａｎ空间Ｌ＾２ａ（Ｄ）上全体Ｔｏｅｐｌｉｔｚ算子的Ｗ闭包等于Ｂ（Ｌ＾２ａ（Ｄ）（定理１），另外，我们给出Ｃ＾ｍ（ｎ＞１）中单位球面Ｓ上的Ｈａｒｄｙ空间Ｈ＾２（Ｓ）上的Ｔｏｅｐｌｉｔｚ算子的一个有趣刻划（命题２）。     

Measures on product spaces and the existence of strong Baire liftings

Some notions are introduced for studying measures on product spaces, the main concept being that of property (*). In case when the topological factors are separable metric spaces, this property is equivalent to the completion regularity. We prove that (*) is preserved under arbitrary products of measure spaces. As a consequence, we deduce a series of related results in measure theory (some of which are known). In particular, the following extension of a result by Losert is obtained: Subject to CH, every product of ₂ many completion regular measures, each supported on any product of ₁ many compact metric spaces admits a strong Baire lifting.     

Noetherian type in topological products

The cardinal invariant Noetherian type Nt(X) of a topological space X was introduced by Peregudov in 1997 to deal with base properties that were studied by the Russian School as early as 1976. We study its behavior in products and box-products of topological spaces. We prove in Section 2:

1. There are spaces X and Y such that Nt(X×Y)< min{Nt(X), Nt(Y)}.
2. In several classes of compact spaces, the Noetherian type is preserved by the operations of forming a square and of passing to a dense subspace.

The Noetherian type of the Cantor Cube of weight \({\aleph _\omega }\) with the countable box topology, \({({2^{{\aleph _\omega }}})_\delta }\) , is shown in Section 3 to be closely related to the combinatorics of covering collections of countable subsets of \({\aleph _\omega }\) . We discuss the influence of principles like \({\square _{{\aleph _\omega }}}\) and Chang’s conjecture for \({\aleph _\omega }\) on this number and prove that it is not decidable in ZFC (relative to the consistency of ZFC with large cardinal axioms). Within PCF theory we establish the existence of an (?₄, ?₁)-sparse covering family of countable subsets of \({\aleph _\omega }\) (Theorem 3.20). From this follows an absolute upper bound of ?₄ on the Noetherian type of \({({2^{{\aleph _\omega }}})_\delta }\) . The proof uses a method that was introduced by Shelah in 1993 [33].     

Approximate extension property of mappings

The extension problem is to determine the extendability of a mapping defined on a closed subset of a space into a nice space such as a CW complex over the whole space. In this paper, we consider the extension problem when the codomains are general spaces. We take a shape theoretic approach to generalize the extension theory so that the codomains are allowed to be general spaces. We extend the notion of extension type which has been defined for the class of CW complexes and introduce the notion of approximate extension type which is defined for general spaces. We define approximate extension dimension analogously to extension dimension, replacing the class of CW complexes by the class of finitistic separable metrizable spaces. For every metrizable space X, we show the existence of approximate extension dimension of X.     

Additivity of quasi-measures

We prove that quasi-measures on compact Hausdorff spaces are countably additive. Contained in this result is a proof that every quasi-measure decomposes uniquely into a measure and a quasi-measure that has no smaller measure beneath it. We also show that it is consistent with the usual axioms of set-theory that quasi-measures on compact Hausdorff spaces are -additive. Finally, we construct an example that places strong restrictions on other forms of additivity.

     

On a question of Silver about gap-two cardinal transfer principles

Assuming the existence of a Mahlo cardinal, we produce a generic extension of Gödel’s constructible universe L, in which the \(\textit{GCH}\) holds and the transfer principles \((\aleph _2, \aleph _0) \rightarrow (\aleph _3, \aleph _1)\) and \((\aleph _3, \aleph _1) \rightarrow (\aleph _2, \aleph _0)\) fail simultaneously. The result answers a question of Silver from 1971. We also extend our result to higher gaps.     

Compact open topology and CW homotopy type

The class of spaces having the homotopy type of a CW complex is not closed under formation of function spaces. In 1959, Milnor proved the fundamental theorem that, given a space and a compact Hausdorff space X, the space Y^X of continuous functions X→Y, endowed with the compact open topology, belongs to . P.J. Kahn extended this in 1982, showing that if X has finite n-skeleton and π_k(Y)=0, k>n.

Using a different approach, we obtain a further generalization and give interesting examples of function spaces where is not homotopy equivalent to a finite complex, and has infinitely many nontrivial homotopy groups. We also obtain information about some topological properties that are intimately related to CW homotopy type.

As an application we solve a related problem concerning towers of fibrations between spaces of CW homotopy type.     

The absence of bases from certain separable linear topological spaces

We give examples of separable linear topological spaces without Shauder-type bases. We prove that every linear set X of dimension ₀2₀ can be provided with a separable locally convex topology for which there is no Shauder-type basis.Translated from Matematicheskie Zametki, Vol. 12, No. 5, pp. 583–589, November, 1972.In conclusion the author wishes to express his gratitude to M. M. Dragilev for his attention to the paper.     

Ends and tangles

We show that an arbitrary infinite graph can be compactified by its \({\aleph _0}\)-tangles in much the same way as the ends of a locally finite graph compactify it in its Freudenthal compactification. In general, the ends then appear as a subset of its \({\aleph _0}\)-tangles. The \({\aleph _0}\)-tangles of a graph are shown to form an inverse limit of the ultrafilters on the sets of components obtained by deleting a finite set of vertices. The \({\aleph _0}\)-tangles that are ends are precisely the limits of principal ultrafilters.The \({\aleph _0}\)-tangles that correspond to a highly connected part, or \({\aleph _0}\)-block, of the graph are shown to be precisely those that are closed in the topological space of its finite-order separations.     

Existentially closed CSA-groups

We study existentially closed CSA-groups. We prove that existentially closed CSA-groups without involutions are simple and divisible, and that their maximal abelian subgroups are conjugate. We also prove that every countable CSA-group without involutions embeds into a finitely generated one having, up to conjugacy, the same maximal abelian subgroups, except maybe the infinite cyclic ones. We deduce from this that there exist 2^₀ countable existentially closed CSA-groups without involutions and that their first-order theories have 2^₀ types over .     

Boolean spaces with countable base but uncountably many orbits

We construct two Boolean spaces with countable bases which have continuum many orbits. Two points are in the same orbit iff there is a homeomorphism of the space which carries one to the other. One of our examples is a primitive Boolean space. J. Donald Monk posed these problems. We don't know if there is a countably based Boolean space with exactly ₁ orbits.Presented by R. S. Pierce.