On a Hölder type estimate for quasisymmetric functions
We give a Hölder type estimate for normalized ρ-quasisymmetric functions, improving some results of J. Zając.
We give a Hölder type estimate for normalized ρ-quasisymmetric functions, improving some results of J. Zając.
Given a quasisymmetric automorphism γ of the unit circle T we define and study a modification Pγ of the classical Poisson integral operator in the case of the unit disk D. The modification is done by means of the generalized Fourier coefficients of γ. For a Lebesgue's integrable complex-valued function f on T, Pγ[f] is a complex-valued harmonic function in D and it coincides with the classical Poisson integral of f provided γ is the identity mapping on T. Our considerations are motivated by the...
Let a,b ∈ z: 0<|z|<1 and let S(a,b) be the class of all univalent functions f that map the unit disk into {a,bwith f(0)=0. We study the problem of maximizing |f’(0)| among all f ∈ S(a,b). Using the method of extremal metric we show that there exists a unique extremal function which maps onto a simply connnected domain bounded by the union of the closures of the critical trajectories of a certain quadratic differential. If a<0
It is shown that the approximate continuity of the dilatation matrix of a quasiregular mapping f at implies the local injectivity and the asymptotic linearity of f at . Sufficient conditions for to behave asymptotically as are given. Some global injectivity results are derived.
We deal with functions given by the formula where are starlike of order and are complex constants. In particular, radii of starlikeness and convexity as well as orders of starlikeness and convexity are found.