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arXiv · 1405.0469

On maximal area integral problem for analytic functions in the starlike family

S. K. Sahoo·N. L. Sharma
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Abstract

For an analytic function $f$ defined on the unit disk $|z|<1$, let $Δ(r,f)$ denote the area of the image of the subdisk $|z|<r$ under $f$, where $0<r\le 1$. In 1990, Yamashita conjectured that $Δ(r,z/f)\le πr^2$ for convex functions $f$ and it was finally settled in 2013 by Obradović and et. al.. In this paper, we consider a class of analytic functions in the unit disk satisfying the subordination relation $zf'(z)/f(z)\prec (1+(1-2β)αz)/(1-αz)$ for $0\le β<1$ and $0<α\le 1$. We prove Yamashita's conjecture problem for functions in this class, which solves a partial solution to an open problem posed by Ponnusamy and Wirths.

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S. K. Sahoo, N. L. Sharma. 2014-08-11. On maximal area integral problem for analytic functions in the starlike family. https://arxiv.org/abs/1405.0469

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