Results 51 to 60 of about 17,964 (136)
A Gromov Hyperbolic metric and Möbius transformations
, 2020 We compare a Gromov hyperbolic metric with the hyperbolic metric in the unit ball or in the upper half space, and prove sharp comparison inequalities between the Gromov hyperbolic metric and some hyperbolic type metrics. We also obtain several sharp distortion inequalities for the Gromov hyperbolic metric under some families of Möbius transformations.
Xu, Xiaoxue, Wang, Gendi, Zhang, Xiaohui
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HNN extensions and embedding theorems for groups
Journal of the London Mathematical Society, Volume 113, Issue 5, May 2026.Abstract The Higman–Neumann–Neumann (HNN) paper of 1949 is a landmark of group theory in the 20th century. The proof of its main theorem covers less than a page and uses only pre‐existing technology, but the construction that it introduced, the HNN extension, quickly became one of the principal tools of combinatorial group theory, widely used to build ...
Martin R. Bridson +1 more
wiley +1 more source
Quasi-geodesic segments and Gromov hyperbolic spaces [PDF]
, 1996 It is known that for a geodesic metric space hyperbolicity in the sense of Gromov implies geodesic stability. In this paper it is shown that the converse is also true.
Bonk, Mario
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Exactness and the topology of the space of invariant random equivalence relations
Proceedings of the London Mathematical Society, Volume 132, Issue 5, May 2026.Abstract We characterize exactness of a countable group Γ$\Gamma$ in terms of invariant random equivalence relations (IREs) on Γ$\Gamma$. Specifically, we show that Γ$\Gamma$ is exact if and only if every weak limit of finite IREs is an amenable IRE.
Héctor Jardón‐Sánchez +3 more
wiley +1 more source
Expositiones Mathematicae, 2005 This is a mini monograph on Gromov hyperbolic spaces, which are not necessarily geodesic or proper. As the author notes, the purpose of the article is to give a fairly detailed treatment of the basic theory of hyperbolic spaces more general than proper and geodesic.
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A characterization of Gromov hyperbolicity of surfaces with variable negative curvature
, 2021 In this paper we show that, in order to check Gromov hyperbolicity of any surface with curvature K≤ −k² < 0, we just need to verify the Rips condition on a very small class of triangles, namely, those contained in simple closed geodesics. This result is,
Tourís, Eva, Portilla, Ana
core
The Kobayashi metric and Gromov hyperbolicity on pseudoconvex domains of finite type in $\mathbb{C}^2$ [PDF]
, 2023 In this paper, we obtain a more precise estimate of Catlin-type distance for smoothly bounded pseudoconvex domain of finite type in $\mathbb{C}^2$. As an application, we get an alternative proof of the Gromov hyperbolicity of this domain equipped with ...
Li, Haichou, Pu, Xingsi, Wang, Lang
core
Non‐amenability of mapping class groups of infinite‐type surfaces and graphs
Bulletin of the London Mathematical Society, Volume 58, Issue 4, April 2026.Abstract This paper completely determines the non‐amenability of the mapping class groups of infinite‐type surfaces, the mapping class groups of locally finite infinite graphs of higher ranks, gives an example of non‐amenable stabiliser of a point at infinity of a coarsely bounded generated hyperbolic Polish group, and exhibits a class of mapping class
Yusen Long
wiley +1 more source
Graphical small cancellation and hyperfiniteness of boundary actions
Journal of the London Mathematical Society, Volume 113, Issue 4, April 2026.Abstract We study actions of (infinitely presented) graphical small cancellation groups on the Gromov boundaries of their coned‐off Cayley graphs. We show that a class of graphical small cancellation groups, including (infinitely presented) classical small cancellation groups, admit hyperfinite boundary actions, more precisely, the orbit equivalence ...
Chris Karpinski +2 more
wiley +1 more source
Uniform growth in small cancellation groups
Journal of the London Mathematical Society, Volume 113, Issue 4, April 2026.Abstract An open question asks whether every group acting acylindrically on a hyperbolic space has uniform exponential growth. We prove that the class of groups of uniform uniform exponential growth acting acylindrically on a hyperbolic space is closed under taking certain geometric small cancellation quotients.
Xabier Legaspi, Markus Steenbock
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