Automatic continuity for homeomorphism groups of noncompact manifolds

一类具有算法可解同胚问题的开曲面

A class of open surfaces with algorithmically solvable homeomorphism problem

本文提出拓扑自动机这一由有限数据定义的非紧流形新类，并证明当维数为2时其同胚问题算法可判定。

Automatic continuity in homeomorphism groups of compact 2-manifolds

We show that any homomorphism from the homeomorphism group of a compact 2-manifold, with the compact-open topology, or equivalently, with the topology of uniform convergence, into a separable topological group is automatically continuous.

Chaotic behavior of countable products of homeomorphism groups

Relationships between a chaotic behavior and closely related properties of topological transitivity, sensitivity to initial conditions, density of closed orbits of homeomorphism groups and their countable products are investigated. We construct numerous new examples of chaotic groups of homeomorphisms of countable products of various metrizable topological spaces, including infinite-dimensional topological manifolds, whose factors can be as noncompact surfaces, so triangulable closed manifolds of an arbitrary dimension.

关于自动连续性的稳定表面分类

Classification of Stable Surfaces with respect to Automatic Continuity

本文研究了稳定表面的同胚群是否具有自动连续性，通过一般框架证明了同胚群的自动连续性，并回答了Mann提出的两个问题。

纯映射类群的自动连续性

Automatic continuity of pure mapping class groups

本文完整分类了使纯映射类群及其紧支撑逼近闭包具有自动连续性的可定向无限型曲面，并证明有限端、无非紧边界时 Map(S) 不具该性质。

几乎所有维数下无边光滑流形的微分同胚群或同胚群上的紧开拓扑是极小的

The compact-open topology on the diffeomorphism or homeomorphism group of a smooth manifold without boundary is minimal in almost all dimensions

该研究证明维数非3的连通光滑流形微分同胚群上紧开拓扑是极小的，进而推得维数非3、4的流形同胚群上该拓扑极小，闭流形等满足自动连续性的情形下它还是唯一可分Hausdorff群拓扑。

On low-codimensional decompositions

Decompositions on manifolds appear in various geometric structures. Necessary and sufficient conditions for quotient spaces of decompositions to be manifolds are widely characterized. We characterize necessary and sufficient conditions to be $k$-manifolds $(k = 1, 2)$, which generalize characterizations in the codimension-$k$ cases for the leaf spaces of foliations, the orbit spaces of group-actions, decomposition spaces of upper semi-continuous decompositions, and leaf class spaces of Riemannian foliation with regular closure. To prove such characterizations, we generalize a characterization …

The compact-open topology on the homeomorphism group of a surface without boundary is minimal

We show that the homeomorphism group of a surface without boundary does not admit a Hausdorff group topology strictly coarser than the compact-open topology. In combination with known automatic continuity results, this implies that the compact-open topology is the unique Hausdorff separable group topology on the group if the surface is closed or the complement in a closed surface of either a finite set or the union of a finite set and a Cantor set.

集合论、逻辑与流形的同胚群

Set theory, logic, and homeomorphism groups of manifolds

研究公理集合论与流形同胚群一阶理论的关系，通过构建性公理（V = L）证明同胚群的一阶刚性等，在正则假设下得出不同结论，还表明无穷公式可确定同胚类和流形类型。

Gluing locally symmetric manifolds: asphericity and rigidity

We use the reflection group trick to glue manifolds with corners that are Borel-Serre compactifications of locally symmetric spaces of noncompact type and obtain aspherical manifolds. We call these \emph{piecewise locally symmetric} manifolds. This class of spaces provide new examples of aspherical manifolds whose fundamental groups have the structure of a complex of groups. These manifolds typically do not admit a locally $\CAT(0)$ metric. We prove that any self homotopy equivalence of such manifolds is homotopic to a homeomorphism. We compute the group of self homotopy equivalences of such a…

Combinatorial fiber bundles and fragmentation of a fiberwise PL-homeomorphism

With a compact PL manifold X we associate a category T(X). The objects of T(X) are all combinatorial manifolds of type X, and morphisms are combinatorial assemblies. We prove that the homotopy equivalence BT (X) \approx BPL(X) holds, where PL(X) is the simplicial group of PL-homeomorphisms. Thus the space BT(X) is a canonical countable (as a CW-complex) model of BPL(X). As a result, we obtain functorial pure combinatorial models for PL fiber bundles with fiber X and a PL polyhedron B as the base. Such a model looks like a T(X)-coloring of some triangulation K of B. The vertices of K are colore…

自相似2维流形的同胚群

Homeomorphism groups of self-similar 2-manifolds

该研究围绕自相似2维流形的同胚群展开，通过综述新旧成果、研究稳定集结构，证明了三项强化/推广型定理，为无限亏格2维流形同胚群的Steinhaus性质提供了首批实例。

从描述角度看的流形分类

Manifold classification from the descriptive viewpoint

本文从描述集合论角度研究流形和李群离散子群的分类问题，揭示了流形同胚问题的Borel复杂性及双曲流形等距关系的分类特性。

Cardinal-indexed classifying spaces for families of subgroups of any topological group

For $G$ a topological group, existence theorems by Milnor (1956), Gelfand-Fuks (1968), and Segal (1975) of classifying spaces for principal $G$-bundles are generalized to $G$-spaces with torsion. Namely, any $G$-space approximately covered by tubes (a generalization of local trivialization) is the pullback of a universal space indexed by the orbit types of tubes and cardinality of the cover. For $G$ a Lie group, via a metric model we generalize the corresponding uniqueness theorem by Palais (1960) and Bredon (1972) for compact $G$. Namely, the $G$-homeomorphism types of proper $G$-spaces over …