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A note on the structural stability of almost one-to-one maps 关于几乎一对一映射的结构稳定性的注释
IF 0.5 4区 数学 Q3 MATHEMATICS Pub Date : 2025-10-17 DOI: 10.1016/j.topol.2025.109641
María Isabel Cortez, Till Hauser
A continuous surjection π:XY between compact Hausdorff spaces induces continuous surjections M(π):M(X)M(Y) and H(π):H(X)H(Y) between the spaces of regular Borel probability measures, and the spaces of closed subsets, respectively. It is well known that H(π) is irreducible if and only if π is irreducible. We show that M(π) is irreducible if and only if π is irreducible. Furthermore, we show that whenever π is almost one-to-one then M(π) and H(π) are almost one-to-one. In particular, we observe that continuous surjections between compact metric spaces are almost one-to-one if and only if H(π) is almost one-to-one and a similar statement about M(π). Finally, we give alternative proofs for some results in [8] regarding semi-open maps.
紧Hausdorff空间间的连续抛射π:X→Y分别在正则Borel概率测度空间和闭子集空间间导出M(π):M(X)→M(Y)和H(π):H(X)→H(Y)连续抛射。众所周知,当且仅当π不可约时,H(π)不可约。我们证明M(π)当且仅当π不可约时是不可约的。进一步证明了当π几乎是一对一时,M(π)和H(π)几乎是一对一的。特别地,我们观察到紧度量空间之间的连续射几乎是一对一的当且仅当H(π)几乎是一对一的,并且关于M(π)也有类似的表述。最后,我们给出了[8]中关于半开放映射的一些结果的替代证明。
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引用次数: 0
Some characterizations on strongly topological gyrogroups 强拓扑陀螺群的一些性质
IF 0.5 4区 数学 Q3 MATHEMATICS Pub Date : 2025-10-17 DOI: 10.1016/j.topol.2025.109639
Jing Song , Meng Bao , Xiaolan Liu , Xuewei Ling
A topological gyrogroup is a gyrogroup endowed with a topology such that the binary operation is jointly continuous and the inverse mapping is also continuous. In this paper, it is shown that a strongly topological gyrogroup G is strongly countably complete if and only if G contains a closed countably compact strong subgyrogroup H such that the quotient space G/H is completely metrizable and the canonical quotient mapping π:GG/H is closed, which gives an affirmative answer to [40, Question 4.11] and it deduces that a strongly topological gyrogroup G is strongly countably complete if and only if it is countably sieve-complete. Then it is claimed that every symmetrizable Hausdorff strongly paratopological gyrogroup with the Baire property is a metrizable strongly topological gyrogroup.
拓扑陀螺群是具有二元运算联合连续且逆映射连续的拓扑结构的陀螺群。本文证明了强拓扑陀螺群G是强可数完备的当且仅当G包含一个闭可数紧强子陀螺群H,使得商空间G/H是完全可度制的,正则商映射π:G→G/H是闭的,给出了对[40,问题4.11]的肯定回答,并推导出强拓扑陀螺群G是强可数完备的当且仅当它是可数筛完备的。然后证明了每一个具有Baire性质的可对称Hausdorff强准拓扑陀螺群都是可度量的强拓扑陀螺群。
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引用次数: 0
A gerbe-like construction in gauge theory 规范理论中的格贝式结构
IF 0.5 4区 数学 Q3 MATHEMATICS Pub Date : 2025-10-17 DOI: 10.1016/j.topol.2025.109638
Mitsuyoshi Adachi
In 2022 Baraglia and Konno showed the following: for a smooth family of a homotopy K3 surface XXπB, if the tangent bundle along the fibers TBX admits a spin structure, then H+(X) also admits a spin structure, where H+(X) is the vector bundle consisting of self-dual harmonic 2-forms. In this paper, we show that TBXπH+(X) admits a canonical spin structure. The proof is carried out by canonically constructing a lifting O(1)-gerbe for the spin structure on H+(X) using the families Seiberg–Witten equations, starting from a lifting O(1)-gerbe for the spin structure on TBX.
Baraglia和Konno在2022年证明:对于同伦K3曲面X→X→πB的光滑族,如果沿纤维TBX的切束承认自旋结构,则H+(X)也承认自旋结构,其中H+(X)是由自对偶调和2型组成的矢量束。在本文中,我们证明了TBX⊕π H+(X)具有正则自旋结构。从TBX上自旋结构的提升O(1)-gerbe开始,利用Seiberg-Witten方程组,通过正则构造H+(X)上自旋结构的提升O(1)-gerbe来证明。
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引用次数: 0
The proximal game and its connections to other games 近端游戏及其与其他游戏的联系
IF 0.5 4区 数学 Q3 MATHEMATICS Pub Date : 2025-10-13 DOI: 10.1016/j.topol.2025.109636
Khulod Almontashery , Paul J. Szeptycki
We introduce a strengthening of the class of the proximal and semi-proximal spaces by restricting the proximal game to totally bounded uniformities. In addition, we examine the connections between the proximal game and two well-known games, one set-theoretic the other topological: the Galvin game and the Gruenhage game.
通过将近端对策限制为完全有界均匀性,我们引入了近端和半近端空间类的强化。此外,我们研究了近端对策与两个著名的对策之间的联系,一个是集合论的,另一个是拓扑论的:Galvin对策和Gruenhage对策。
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引用次数: 0
A discrete topological complexity of discrete motion planning 离散运动规划的离散拓扑复杂性
IF 0.5 4区 数学 Q3 MATHEMATICS Pub Date : 2025-10-10 DOI: 10.1016/j.topol.2025.109634
Hadi Hassanzada, Hamid Torabi, Hanieh Mirebrahimi, Ameneh Babaee
In this paper, we present a framework for discrete motion planning tailored for robots that operate in a discrete manner. Furthermore, we extend the concept of r-discrete homotopy as discrete (s,r)-homotopy. Utilizing this framework, we investigate the notion of discrete topological complexity, which is defined as the least number of motion planning algorithms necessary for discrete movement. We establish several properties related to discrete topological complexity; for example, we demonstrate that discrete motion planning within a metric space X is feasible if and only if X is a discrete contractible space. Additionally, we show that the discrete topological complexity is solely determined by the strictly discrete homotopy type of the spaces involved.
在本文中,我们提出了一个为以离散方式操作的机器人量身定制的离散运动规划框架。进一步,我们将r-离散同伦的概念推广为离散(s,r)-同伦。利用这个框架,我们研究了离散拓扑复杂性的概念,它被定义为离散运动所需的最少数量的运动规划算法。我们建立了与离散拓扑复杂性相关的几个性质;例如,我们证明了度量空间X内的离散运动规划当且仅当X是一个离散可收缩空间时是可行的。此外,我们还证明了离散拓扑复杂度完全取决于所涉及空间的严格离散同伦类型。
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引用次数: 0
Guest Editorial for Special Issue 特刊客座社论
IF 0.5 4区 数学 Q3 MATHEMATICS Pub Date : 2025-10-10 DOI: 10.1016/j.topol.2025.109632
Bob Stephenson (Guest Editor), Alan Dow (Guest Editor), Paul Szeptycky (Guest Editor), Todd Eisworth (Guest Editor)
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引用次数: 0
Generalizations of chainability and compactness, and the hypertopologies 链性和紧性的推广,以及超拓扑
IF 0.5 4区 数学 Q3 MATHEMATICS Pub Date : 2025-10-10 DOI: 10.1016/j.topol.2025.109635
Ajit Kumar Gupta , Saikat Mukherjee
We define two properties for subsets of a metric space. One of them is a generalization of chainability, finite chainability, and Menger convexity for metric spaces; and the other extends the notion of compactness for subsets of a metric space. We establish several fundamental results concerning these two properties. Further, in the context of these properties, we study the Hausdorff metric and derive the relations among Hausdorff, Vietoris, and locally finite hypertopologies on the collection of nonempty closed subsets of a metric space.
我们定义了度量空间子集的两个性质。其中之一是对度量空间的链性、有限链性和门格尔凸性的推广;另一个扩展了度量空间子集的紧性概念。我们建立了关于这两个性质的几个基本结果。进一步,在这些性质的背景下,我们研究了Hausdorff度量,并推导了度量空间的非空闭子集集合上的Hausdorff、Vietoris和局部有限超拓扑之间的关系。
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引用次数: 0
The homology groups of finite cyclic coverings of line arrangement complements 线排列补的有限循环覆盖的同调群
IF 0.5 4区 数学 Q3 MATHEMATICS Pub Date : 2025-10-10 DOI: 10.1016/j.topol.2025.109633
Yongqiang Liu , Wentao Xie
In this paper, we study the first homology group of finite cyclic covering of complex line arrangement complement. We show that this first integral homology group is torsion-free under certain condition similar to the one used by Cohen-Dimca-Orlik [3, Theorem 1]. In particular, this includes the case of the Milnor fiber, which generalizes the previous results obtained by Williams [36, Main Theorem 1] for complexified line arrangement to any complex line arrangement.
本文研究了复线排列补的有限循环覆盖的第一同调群。在与Cohen-Dimca-Orlik[3,定理1]相似的条件下,证明了第一个积分同调群是无扭转的。特别地,这包括Milnor纤维的情况,它将Williams [36, Main Theorem 1]先前得到的关于复线排列的结果推广到任何复线排列。
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引用次数: 0
On o-free sequences and compacta 关于o自由序列与紧性
IF 0.5 4区 数学 Q3 MATHEMATICS Pub Date : 2025-10-06 DOI: 10.1016/j.topol.2025.109631
Nathan Carlson
We use the notion of an o-free sequence to give new bounds for the cardinality of Hausdorff spaces and regular spaces. There are several implications for compacta. One is that if X is a compactum then w(X)hL(X)ot(X), where ot(X) is the o-tightness introduced by Tkachenko. Another is that |X|hL(X)ot(X)wψc(X) if X is a compactum. This is shown to be a strict improvement of Arhangel'skiĭ's bound 2ψ(X). Finally, we show |X|hL(X)ot(X)πχ(X) if X is a homogeneous compactum. We note hL(X)ot(X)πχ(X)2t(X) for such spaces, where 2t(X) is de la Vega's bound for the cardinality of homogeneous compacta.
我们利用无0序列的概念给出了Hausdorff空间和正则空间的基数的新边界。compact有几个含义。一是如果X是紧致,则w(X)≤hL(X)ot(X),其中ot(X)为Tkachenko引入的o紧性。另一个是|X|≤hL(X)ot(X)wψc(X),如果X是紧致的。这被证明是Arhangel'ski 's界2ψ(X)的严格改进。最后,我们证明了如果X是齐次紧致,|X|≤hL(X)ot(X)πχ(X)。我们注意到hL(X)ot(X)πχ(X)≤2t(X),其中2t(X)是齐次紧的基数的de la Vega界。
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引用次数: 0
Weak approximation by points in function spaces and in the power of Arens' space 函数空间和阿伦斯空间幂中的点的弱逼近
IF 0.5 4区 数学 Q3 MATHEMATICS Pub Date : 2025-10-06 DOI: 10.1016/j.topol.2025.109629
Kenichi Tamano , Stevo Todorčević
We study the weak approximation by points (WAP) in function spaces Ck(X) and Cp(X) and in the power S2ω of Arens' space S2. The following two results are shown:
(1) The space S2ω, which can be embedded in Ck(ωω) and Cp(ωω), is WAP, answering a question of G. Gruenhage, B. Tsaban, and L. Zdomskyy.
(2) Cp(ωω) is not WAP.
研究了函数空间Ck(X)和Cp(X)以及Arens空间S2的S2ω幂上的点弱逼近(WAP)。结果表明:(1)空间S2ω可以嵌入到Ck(ωω)和Cp(ωω)中,是WAP,回答了G. Gruenhage、B. Tsaban和L. zdomsky的问题。(2) Cp(ωω)不是WAP。
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引用次数: 0
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Topology and its Applications
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