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arXiv 0908.3316math.DS
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实线性分式变换的拓扑传递半群作用

Topologically transitive semigroup actions of real linear fractional transformations

Siena University(锡耶纳大学)

Mohammad Javaheri

AI总结:

该研究刻画了实线性分式变换半群在闭子区间上拓扑传递的映射对,证明其与超循环性等等价,还分类了仿射映射半群的作用类型,指出线性分式变换半群作用的传递性边界。

摘要:

设$F_I = \{f:I\to I \mid f(x)=(Ax+B)/(Cx+D),\\ AD-BC\neq 0\}$,其中$I$是$\mathbb{R}$的一个真闭子区间。我们刻画了所有满足以下条件的$f,g\in F_I$对:由$f$和$g$生成的半群$\langle f,g \rangle$在$I$上的作用是拓扑传递的。结果表明,对于这类映射对,拓扑传递性、超循环性以及每个内部轨道的稠密性是等价的。利用$I$的Hilbert度量,我们证明$F_I$中任意生成元个数的子半群都不会在$I$上实现弱拓扑混合作用。我们对$\mathbb{R}$上仿射映射的映射对进行分类,其半群作用分别为拓扑传递、弱拓扑混合或超循环,且证明这类作用永远不是3-传递的。相比之下,存在实线性分式变换的映射对,其在$\mathbb{R}$上的半群作用是拓扑3-传递的,而任何线性分式变换的半群都不是4-传递的。

英文摘要:

Let $F_I=\{f:I\to I \mid f(x)=(Ax+B)/(Cx+D),\ AD-BC\neq 0\}$, where $I$ is a proper closed subinterval of $\mathbb{R}$. We describe all pairs $f,g\in F_I$ for which the action of the semigroup $\langle f,g \rangle$ generated by $f$ and $g$ is topologically transitive on $I$. It turns out that for such pairs topological transitivity, hypercyclicity, and density of every interior orbit are equivalent. Using the Hilbert metric of $I$ we show that no subsemigroup of $F_I$, with any number of generators, acts in a weakly topologically mixing way on $I$. We classify the pairs of affine maps of $\mathbb{R}$ whose semigroup action is topologically transitive, weakly topologically mixing, or hypercyclic, and we show that such an action is never $3$-transitive. In contrast, there are pairs of real linear fractional transformations whose semigroup action on $\mathbb{R}$ is topologically $3$-transitive, while no semigroup of linear fractional transformations is $4$-transitive.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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