منابع مشابه
Covering Spaces and Discrete Groups
We have already met covering spaces in Chapter 2, where our discussion was geometric and basically limited to definitions and examples. In this chapter, we return to this topic from a more algebraic point of view, which will allow us to produce numerous examples coming from group actions and to classify all covering spaces with given base (provided the latter is “nice” enough). The main tools w...
متن کاملIndecomposable Groups Acting on Hyperbolic Spaces
We obtain a number of finiteness results for groups acting on hy-perbolic spaces and R-trees. In particular we show that a torsion-free locally quasiconvex hyperbolic group has only finitely many conjugacy classes of n-generated one-ended subgroups. We also prove an acylindrical accessibility theorem for groups acting on R-trees.
متن کاملAlmost simple groups with Socle $G_2(q)$ acting on finite linear spaces
After the classification of the flag-transitive linear spaces, the attention has been turned to line-transitive linear spaces. In this article, we present a partial classification of the finite linear spaces $mathcal S$ on which an almost simple group $G$ with the socle $G_2(q)$ acts line-transitively.
متن کاملSemigroup Actions, Covering Spaces and Schützenberger Groups
We associate a 2-complex to the following data: a presentation of a semigroup S and a transitive action of S on a set V by partial transformations. The automorphism group of the action acts properly discontinuously on this 2-complex. A sufficient condition is given for the 2-complex to be simply connected. As a consequence we obtain simple topological proofs of results on presentations of Schüt...
متن کاملUniform growth of groups acting on Cartan-Hadamard spaces
We say that Γ has uniform exponential growth if Ent Γ > 0. In [11], remarque 5.12, M. Gromov raised the question whether exponential growth always implies uniform exponential growth. The answer is negative, indeed, in [14] J.S. Wilson gave examples of finitely generated groups of exponential growth and non uniform exponential growth. Nevertheless, exponential growth implies uniform exponential ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Colloquium Mathematicum
سال: 1980
ISSN: 0010-1354,1730-6302
DOI: 10.4064/cm-43-1-81-89