Let T(Δ) be the universal Teichmüller space on the unit disk Δ and T₀(Δ) be the set of asymptotically conformal classes in T(Δ). Suppose that μ is a Beltrami differential on Δ with [μ] ∈ T₀(Δ). It is an interesting question whether [tμ] belongs to T₀(Δ) for general t ≠ 0, 1. In this paper, it is shown that there exists a Beltrami differential μ ∈ [0] such that [tμ] is a non-trivial non-Strebel point for any .
Estudiamos algunas cuestiones estructurales acerca del espacio localmente convexo HV∞, que está formado por funciones analíticas en el disco unidad abierto. Construimos una descomposición atómica de este espacio, usando un retículo de puntos del disco unidad que es más denso que el usual. También demostramos que HV∞ no es nuclear.
Given an orientation-preserving homeomorphism of the plane, a rotation number can be associated with each locally attracting fixed point. Assuming that the homeomorphism is dissipative and the rotation number vanishes we prove the existence of a second fixed point. The main tools in the proof are Carath´eodory prime ends and fixed point index. The result is applicable to some concrete problems in the theory of periodic differential equations.
We give an upper bound for the order of an automorphism of a Riemann surface with two fixed points. The main results are presented in Theorems 1.4 and 2.4.