Rips conjectured that a non-elementary word hyperbolic group is cohopfian if and only if it is freely indecomposable. The results and examples in this paper show that cohopficity phenomenon in the case of word hyperbo...Rips conjectured that a non-elementary word hyperbolic group is cohopfian if and only if it is freely indecomposable. The results and examples in this paper show that cohopficity phenomenon in the case of word hyperbolic group with torsion is much more complicated than the conjecture. In particular, the cohopficity of such groups is not determined by the numbers of their ends and the cohopficity is not preserved by finite index subgroups. Our results and examples arise from Kleinian groups. Orbifold structures and orbifold maps are the new tools in our discussions.展开更多
In this paper, we study exhaustions, referred to as p-restrictions, of arbitrary nonelementary Kleinian groups with at most finitely many bounded parabolic elements. Special emphasis is put on the geometrically infini...In this paper, we study exhaustions, referred to as p-restrictions, of arbitrary nonelementary Kleinian groups with at most finitely many bounded parabolic elements. Special emphasis is put on the geometrically infinite case, where we obtain that the limit set of each of these Kleinian groups contains an infinite family of closed subsets, referred to as p-restricted limit sets, such that there is a Poincaré series and hence an exponent of convergence δp, canonically associated with every element in this family. Generalizing concepts which are well known in the geometrically finite case, we then introduce the notion of p-restricted Patterson measure, and show that these measures are non-atomic, δp-harmonic, δp-subconformal on special sets and δp-conformal on very special sets. Furthermore, we obtain the results that each p-restriction of our Kleinian group is of δp-divergence type and that the Hausdorff dimension of the p-restricted limit set is equal to δp.展开更多
本文首先得到了SL(2,Γ_n)中Klein群的一个不等武,并给出了它的两个应用;然后证明了对SL(2,Γ_n)中的非初等群G,若G中的任意斜驶元素f满足tr^2(f)>4且当∞■fix(f)时tr(f)=tr(f),则存在h∈SL(2,Γn)使得hGh^(-1) C SL(2,R).此结果是M...本文首先得到了SL(2,Γ_n)中Klein群的一个不等武,并给出了它的两个应用;然后证明了对SL(2,Γ_n)中的非初等群G,若G中的任意斜驶元素f满足tr^2(f)>4且当∞■fix(f)时tr(f)=tr(f),则存在h∈SL(2,Γn)使得hGh^(-1) C SL(2,R).此结果是Maskit相关结果的推广.展开更多
基金supported by MSTC and Outstanding Youth Grant of NSFC
文摘Rips conjectured that a non-elementary word hyperbolic group is cohopfian if and only if it is freely indecomposable. The results and examples in this paper show that cohopficity phenomenon in the case of word hyperbolic group with torsion is much more complicated than the conjecture. In particular, the cohopficity of such groups is not determined by the numbers of their ends and the cohopficity is not preserved by finite index subgroups. Our results and examples arise from Kleinian groups. Orbifold structures and orbifold maps are the new tools in our discussions.
基金Research supported by the Schweizer Nationalfonds No. 20-61379.00 European Project TMR "Geometric Analysis" ACR-OFES No. UE 00.0349
文摘In this paper, we study exhaustions, referred to as p-restrictions, of arbitrary nonelementary Kleinian groups with at most finitely many bounded parabolic elements. Special emphasis is put on the geometrically infinite case, where we obtain that the limit set of each of these Kleinian groups contains an infinite family of closed subsets, referred to as p-restricted limit sets, such that there is a Poincaré series and hence an exponent of convergence δp, canonically associated with every element in this family. Generalizing concepts which are well known in the geometrically finite case, we then introduce the notion of p-restricted Patterson measure, and show that these measures are non-atomic, δp-harmonic, δp-subconformal on special sets and δp-conformal on very special sets. Furthermore, we obtain the results that each p-restriction of our Kleinian group is of δp-divergence type and that the Hausdorff dimension of the p-restricted limit set is equal to δp.
基金The research was partly supported by NSFs of China and Zhejiang Province, Soft Project, of ScienceTechnology of Hunan Province and the Foundation for Scholars back from Foreign Countries
文摘本文首先得到了SL(2,Γ_n)中Klein群的一个不等武,并给出了它的两个应用;然后证明了对SL(2,Γ_n)中的非初等群G,若G中的任意斜驶元素f满足tr^2(f)>4且当∞■fix(f)时tr(f)=tr(f),则存在h∈SL(2,Γn)使得hGh^(-1) C SL(2,R).此结果是Maskit相关结果的推广.
