2003International Journal of Mathematics and Mathematical SciencesOpen access

Subordination criteria for starlikeness and convexity

Rasoul Aghalary, Jay M. Jahangiri

Open full text 0 citations

Abstract

For functions p analytic in the open unit disc U = {z : |z| < 1} with the normalization p(0) = 1, we consider the families 𝒫[A, −1], −1 < A ≤ 1, consisting of p such that p(z) is subordinate to (1 + Az)/(1 − z) in U and 𝒫(1, b), b > 0, consisting of p, which have the disc formulation |p − 1| < b in U. We then introduce subordination criteria for the choice of p(z) = zf′(z)/f(z), where f is analytic in U and normalized by f(0) = f′(0) − 1 = 0. We also obtain starlikeness and convexity conditions for such functions f and consequently extend and, in some cases, improve the corresponding previously known results.

Open-access reader

About this research paper

What this paper is about

For functions p analytic in the open unit disc U = {z : |z| < 1} with the normalization p(0) = 1, we consider the families 𝒫[A, −1], −1 < A ≤ 1, consisting of p such that p(z) is subordinate to (1 + Az)/(1 − z) in U and 𝒫(1, b), b > 0, consisting of p, which have the disc formulation |p − 1| < b in U. We then introduce subordination criteria for the choice of p(z) = zf′(z)/f(z), where f is analytic in U and normalized by f(0) = f′(0) − 1 = 0. We also obtain starlikeness and convexity conditions for such functions f and consequently extend and, in some cases, improve the corresponding previously known results.

Why it matters

A significance statement is not available in the OpenAlex record.

Key contribution

A contribution statement is not available in the OpenAlex record.

Method / approach

Method details are not available in the OpenAlex metadata.

Main findings

Findings are not separately available in the OpenAlex metadata.

Limitations

Limitations are not available in the OpenAlex metadata.

Applications

Application details are not available in the OpenAlex metadata.

Available abstract

For functions p analytic in the open unit disc U = {z : |z| < 1} with the normalization p(0) = 1, we consider the families 𝒫[A, −1], −1 < A ≤ 1, consisting of p such that p(z) is subordinate to (1 + Az)/(1 − z) in U and 𝒫(1, b), b > 0, consisting of p, which have the disc formulation |p − 1| < b in U. We then introduce subordination criteria for the choice of p(z) = zf′(z)/f(z), where f is analytic in U and normalized by f(0) = f′(0) − 1 = 0. We also obtain starlikeness and convexity conditions for such functions f and consequently extend and, in some cases, improve the corresponding previously known results.

Key concepts: Mathematics, Convexity, Subordination (linguistics), Normalization (sociology), Unit disk, Analytic function, Combinatorics, Pure mathematics

Related papers

Back to paper searchBrowse research topicsOriginal source
Subordination criteria for starlikeness and convexity — Research Paper | ScholarLens