approximations of convex, subharmonic, and plurisubharmonic functions
Given a function on with and , a procedure is exhibited for obtaining on a (finite) superharmonic majorant of the functionwhere is a certain (large) absolute constant. This leads to fairly constructive proofs of the two main multiplier theorems of Beurling and Malliavin. The principal tool used is a version of the following lemma going back almost surely to Beurling: suppose that , positive and bounded away from 0 on , is such that and denote, for any constant and each , the unique...
We first prove that the convolution of a normalized right half-plane mapping with another subclass of normalized right half-plane mappings with the dilatation [...] −z(a+z)/(1+az) is CHD (convex in the horizontal direction) provided [...] a=1 or [...] −1≤a≤0 . Secondly, we give a simply method to prove the convolution of two special subclasses of harmonic univalent mappings in the right half-plane is CHD which was proved by Kumar et al. [1, Theorem 2.2]. In addition, we derive the convolution...