Subordinations by alpha-convex functions

[摘要] References(11)Let H(U) be the space of analytic functions in the unit disk U and let \mathscr{D}={φ∈H(U):φ(0)=1, φ(z)≠0, z∈U}. For the functions φ, φ∈\mathscr{D} we will determine simple sufficient conditions such that[\frac{φ(z)}{φ(z)+(1/γ)zφ'(z)}]1/βf(z) {\prec} k(z){⇒}Iφ, φ;β, γ[f](z) {\prec} k(z), for all k∈\mathscr{M}1/β', whereIφ, φ;β, γ[f](z)=[\frac{γ}{zγφ(z)}∫0zfβ(t)tγ−1φ(t) dt]1/βand \mathscr{M}1/β' represents the class of 1/β-convex functions (not necessarily normalized).In particular, we will give sufficient conditions on φ and φ so that the operators Iφ, φ;β, γ are averaging operators on certain subsets of H(U). In addition, some particular cases of the main result, obtained for appropriate choices of the φ and φ functions, will also be given.

[学科分类] 数学（综合）

[关键词] Differential subordination;averaging operator;subordination chain;univalent function;alpha-convex function