The Journal of Geometric Analysis ( IF 1.2 ) Pub Date : 2021-03-23 , DOI: 10.1007/s12220-021-00653-w Maria Kourou
Let \((\phi _t)_{t \ge 0}\) be a semigroup of holomorphic self-maps of the unit disk \({{\,\mathrm{{\mathbb {D}}}\,}}\) with Denjoy–Wolff point \(\tau =1\). The angular derivative is \(\phi _t^{\prime }(1)= e^{-\lambda t}\), where \(\lambda \ge 0\) is the spectral value of \((\phi _t)\). If \(\lambda >0\) the semigroup is hyperbolic, otherwise it is parabolic. Suppose K is a compact non-polar subset of \({{\,\mathrm{{\mathbb {D}}}\,}}\). We specify the type of the semigroup by examining the asymptotic behavior of \(\phi _t(K)\). We provide a representation of the spectral value of the semigroup with the use of several potential theoretic quantities, e.g., harmonic measure, Green function, extremal length, condenser capacity.
中文翻译:
全纯函数半群的谱值
令\((\ phi _t)_ {t \ ge 0} \)是单位磁盘\({{\,\ mathrm {{\ mathbb {D}}} \,}}的全纯自映射的半群\)和Denjoy–Wolff点\(\ tau = 1 \)。角导数为\(\ phi _t ^ {\ prime}(1)= e ^ {-\ lambda t} \),其中\(\ lambda \ ge 0 \)是\((\ phi _t )\)。如果\(\ lambda> 0 \),则半群是双曲的,否则它是抛物线的。假设K是\({{\,\ mathrm {{\ mathbb {D}}} \ ,,}} \)的紧凑非极性子集。我们通过检查\(\ phi _t(K)\)的渐近行为来指定半群的类型。我们使用几个潜在的理论量来表示半群的光谱值,例如谐波测度,格林函数,极值长度,电容器容量。