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We classify all group topologies coarser than the topology of stabilizers of finite sets in the case of automorphism groups of countable free-homogeneous structures, Urysohn space and Urysohn sphere, among other related results.

Logic · Mathematics 2024-02-21 Zaniar Ghadernezhad , Javier de la Nuez González

We study geometric and topological properties of locally compact, geodesically complete spaces with an upper curvature bound. We control the size of singular subsets, discuss homotopical and measure-theoretic stratifications and regularity…

Differential Geometry · Mathematics 2018-07-19 Alexander Lytchak , Koichi Nagano

We study the properties of geodesic currents on free groups, particularly the "intersection form" that is similar to Bonahon's notion of the intersection number between geodesic currents on hyperbolic surfaces.

Group Theory · Mathematics 2007-05-23 Ilya Kapovich

We consider automorphism groups of some countably categorical structures and their precompact expansions. We prove that automorphism groups of omega-stable omega-categorical structures have metrizable universal minimal flows. We also study…

Logic · Mathematics 2014-12-23 Aleksander Ivanov

We study the compactness problem for moduli spaces of holomorphic supercurves which, being motivated by supergeometry, are perturbed such as to allow for transversality. We give an explicit construction of limiting objects for sequences of…

Symplectic Geometry · Mathematics 2015-02-24 Josua Groeger

We prove a compactness result for holomorphic curves with boundary on an immersed Lagrangian submanifold with clean self-intersection. As a consequence, we show that the number of intersections of such holomorphic curves with the…

Symplectic Geometry · Mathematics 2009-03-13 Kai Cieliebak , Tobias Ekholm , Janko Latschev

It is shown that certain diffeomorphism or homeomorphism groups with no restriction on support of an open manifold with finite number of ends are bounded. It follows that these groups are uniformly perfect. In order to characterize the…

Differential Geometry · Mathematics 2011-04-20 Tomasz Rybicki

We prove a smooth compactness theorem for the space of embedded self-shrinkers in $\RR^3$. Since self-shrinkers model singularities in mean curvature flow, this theorem can be thought of as a compactness result for the space of all…

Differential Geometry · Mathematics 2009-07-16 Tobias H. Colding , William P. Minicozzi

Given a compact Riemannian manifold with boundary, we prove that the space of embedded, which may be improper, free boundary minimal hypersurfaces with uniform area and Morse index upper bound is compact in the sense of smoothly graphical…

Differential Geometry · Mathematics 2021-01-27 Qiang Guang , Zhichao Wang , Xin Zhou

This is a biased survey for the Johnson homomorphisms of the automorphism groups of free groups. We just exposit some well known facts and recent developments for the Johnson homomorphisms and its related topics.

Algebraic Topology · Mathematics 2013-06-11 Takao Satoh

Part 1 : We remark that the conjugacy problem for pairs of hyperbolic au- tomorphisms of a finitely presented group (typically a free group) is decidable. The solution that we propose uses the isomorphism problem for the suspensions, and…

Group Theory · Mathematics 2020-07-20 François Dahmani

In this paper we study the automorphism group of the procongruence mapping class group through its action on the associated procongruence curve and pants complexes. Our main result is a rigidity theorem for the procongruence completion of…

Geometric Topology · Mathematics 2024-04-24 Marco Boggi , Louis Funar

We show that every homomorphism from the infinite-dimensional unitary or orthogonal group to a separable group is continuous.

Functional Analysis · Mathematics 2011-09-07 Todor Tsankov

We consider the actions of (semi)groups on a locally compact group by automorphisms. We show the equivalence of distality and pointwise distality for the actions of a certain class of groups. We also show that a compactly generated locally…

Dynamical Systems · Mathematics 2019-03-27 C. R. E. Raja , Riddhi Shah

We show that a relatively ergodic extension of measure-preserving dynamical systems has relative discrete spectrum if and only if it can be represented as a skew-product by a bundle of compact homogeneous spaces. Our result holds without…

Dynamical Systems · Mathematics 2025-05-16 Nikolai Edeko , Asgar Jamneshan , Henrik Kreidler

We prove a compactness theorem for holomorphic curves in 4-dimensional symplectizations that have embedded projections to the underlying 3-manifold. It strengthens the cylindrical case of the SFT compactness theorem by using intersection…

Symplectic Geometry · Mathematics 2008-03-07 Chris Wendl

This paper exploits adjacencies between the orbits of an ordered set P and a consequence of the classification of finite simple groups to, in many cases, exponentially bound the number of automorphisms. Results clearly identify the…

Combinatorics · Mathematics 2023-09-12 Bernd S. W. Schröder

Necessary and sufficient conditions for the exactness (in the algebraic sense) of certain sequences of continuous group homomorphisms are established.

Functional Analysis · Mathematics 2025-06-23 Dinamérico P. Pombo

In this note we study some properties of topological entropy for non-compact non-metrizable spaces. We prove that if a uniformly continuous self-map $f$ of a uniform space has topological shadowing property then the map $f$ has positive…

Dynamical Systems · Mathematics 2016-11-30 Seyyed Alireza Ahmadi

We study the Lipschitz structures on the geodesic compactification of a regular tree, that are preserved by the automorphism group. They are shown to be similar to the compactifications introduced by William Floyd, and a complete…

Metric Geometry · Mathematics 2008-12-18 Benoit Kloeckner