共查询到20条相似文献，搜索用时 0 毫秒
1.
It is not known if there is a 2-to-1 map from a continuum onto a tree-like continuum. In fact, it is not known if there is a 2-to-1 map onto a hereditarily decomposable tree-like continuum. We show that the domain of such a map would have to contain an indecomposable continuum. 相似文献
2.
A hereditarily indecomposable tree-like continuum without the fixed point property is constructed. The example answers a question of Knaster and Bellamy. 相似文献
3.
In 1947, W.H. Gottschalk proved that no dendrite is the continuous, exactly -to-1 image of any continuum if . Since that time, no other class of continua has been shown to have this same property. It is shown that no hereditarily indecomposable tree-like continuum is the continuous, exactly -to-1 image of any continuum if . 相似文献
4.
Let be a metric continuum and let denote the space of subcontinua of with the Hausdorff metric. We settle a longstanding problem showing that if then . The special structure and properties of hereditarily indecomposable continua are applied in the proof. 相似文献
5.
We prove the following theorems: Theorem 1. Let be an -dimensional hereditarily indecomposable continuum. Then there exist -dimensional hereditarily indecomposable continua and monotone maps such that is an embedding and the space of all subcontinua of is embeddable in by . Theorem 2. For every open monotone map with non-trivial sufficiently small fibers on a finite dimensional hereditarily indecomposable continuum with there exists a -dimensional subcontinuum such that and the restriction of to is also monotone and open. The connection between these theorems and other results in Hyperspace theory is studied. 相似文献
6.
We prove that every separable infinite dimensional complex Banach space admits a hypercyclic uniformly continuous semigroup. We also prove that there exist Banach spaces admitting no chaotic strongly continuous semigroups. 相似文献
7.
This paper shows that every non-separable hereditarily indecomposable Banach space admits an equivalent strictly convex norm, but its bi-dual can never have such a one; consequently, every non-separable hereditarily indecomposable Banach space has no equivalent locally uniformly convex norm. 相似文献
9.
In this paper we first discuss the relations between some G-M-type spaces, and the previous eight kinds of G-M-type Banach spaces are merged into four different kinds. Then we build a Generalized Operator Extension Theorem, and introduce the concept of complete minimal sequences. Some sufficient and necessary conditions under which a Banach space is a hereditarily indecomposable space are given. Finally, we give some characterizations of hereditarily indecomposable Banach Spaces. 相似文献
10.
结合自己的工作，对Gowers-Maurey系列成果获Fields奖以来的研究的新动态作一综述。本是上篇，主要讨论含遗传不可分解空间在内的G－M型空间的若干品种。 相似文献
11.
We answer a question of Yohe by showing that there exists a family of continuum many topologically different hereditarily indecomposable Cantor manifolds without any non-trivial weakly infinite-dimensional subcontinua. This family may consist either of compacta containing one-dimensional subsets or of compacta containing no weakly infinite-dimensional subsets of positive dimension. 相似文献
12.
It is shown that every separable Banach space universal for the class of reflexive Hereditarily Indecomposable space contains isomorphically and hence it is universal for all separable spaces. This result shows the large variety of reflexive H.I. spaces. 相似文献
13.
Suppose that X, Y are two real Banach Spaces. We know that for a standard ε-isometry f : X → Y, the weak stability formula holds and by applying the formula we can induce a closed subspace N of *. In this paper, by using again the weak stability formula, we further show a sufficient and necessary condition for a standard ε-isometry to be stable in assuming that N is w*-closed in Y*.Making use of this result, we improve several known results including Figiel's theorem in reflexive spaces.We also prove that if, in addition, the space Y is quasi-reflexive and hereditarily indecomposable, then L(f)≡span[f(X)] contains a complemented linear isometric copy of X; Moreover, if X =Y, then for every e-isometry f: X → X, there exists a surjective linear isometry S:X → X such that f-S is uniformly bounded by 2ε on X. 相似文献
14.
The following dichotomy is proved. Every Banach space either contains a subspace isomorphic to , or it has an infinite-dimensional closed subspace which is a quotient of a Hereditarily Indecomposable (H.I.) separable Banach space. In the particular case of , it is shown that the space itself is a quotient of a H.I. space. The factorization of certain classes of operators, acting between Banach spaces, through H.I. spaces is also investigated. Among others it is shown that the identity operator admits a factorization through a H.I. space. The same result holds for every strictly singular operator . Interpolation methods and the geometric concept of thin convex sets together with the techniques concerning the construction of Hereditarily Indecomposable spaces are used to obtain the above mentioned results. 相似文献
15.
We present a method for describing all indecomposable subcontinua of . This method enables us to construct in a new subcontinuum of . We also show that the nontrivial layers of standard subcontinua can be described by our method. This allows us to construct a layer with a proper dense -subset and bring the number of (known) nonhomeomorphic subcontinua of to 14. 相似文献
16.
It is shown that a continuum that is an space in the sense of Michael must be hereditarily decomposable. This improves known results, thereby providing more evidence that such continua must be dendrites. 相似文献
17.
A compact space is Valdivia compact if it can be embedded in a Tikhonov cube in such a way that the intersection is dense in , where is the sigma-product ( the set of points with countably many non-zero coordinates). We show that there exists a compact connected Abelian group of weight which is not Valdivia compact, and deduce that Valdivia compact spaces are not preserved by open maps. 相似文献
18.
最近,ＧｏｗｅｒｓＷ．Ｔ．和ＭａｕｒｅｙＢ．构造出第一例遗传不可分解空间,否定地解决了无条件基序列问题,由此导致了Ｂａｎａｃｈ空间的结构理论研究中系列问题的解决,本综述介绍这一新动向,反映了Ｇ－Ｍ系列成果,全文分为七个部分,１个历史回顾与问题沿革;２．Ｇ－Ｍ空间ＸＧ１及其遗传不可分解性质,３．关于空间ＸＧ１上的算子构成;４个关于共轭空间ＸＧ１,５．关于Ｇ－Ｍ的系列成果,６．Ｇ－Ｍ型空间构造的 相似文献
19.
Continua that are approximative absolute neighborhood retracts (AANR's) are characterized as absolute terminal retracts, i.e.,
retracts of continua in which they are embedded as terminal subcontinua. This implies that any AANR continuum has a dense
arc component, and that any ANR continuum is an absolute terminal retract. It is proved that each absolute retract for any
of the classes of: tree-like continua, λ-dendroids, dendroids, arc-like continua and arc-like λ-dendroids is an approximative
absolute retract (so it is an AANR). Consequently, all these continua have the fixed point property, which is a new result
for absolute retracts for tree-like continua. Related questions are asked. 相似文献
20.
We generalize two classes of D-type positive linear maps by permutations. For the first class, we discuss their indecomposability and give conditions when they are indecomposable and decomposable. For the other class, we show that they are atomic. 相似文献
|
