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On extensions of the Open Door Lemma

  • Mostafa Amani , Rasoul Aghalary , Ali Ebadian and Nak Eun Cho EMAIL logo
Published/Copyright: March 28, 2022
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Abstract

The Open Door Lemma is the well-known famous result due to Miller and Mocanu that provides a sufficient condition for an analytic function on the unit disk to have positive real part. This lemma has already been corrected by Kuroki and Owa for non-real initial point. Also, Li and Sugawa extended the Open Door Lemma in a such way that an analytic function takes its values in the given symmetric sector. Now, by the same methods, we provide a sufficient condition for an analytic function to take its values in the asymmetric arbitrary sector.


The fourth author was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (No. 2019R1I1A3A01050861)



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  1. Communicated by Stanisława Kanas

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Received: 2020-05-20
Accepted: 2021-03-31
Published Online: 2022-03-28
Published in Print: 2022-04-26

© 2022 Mathematical Institute Slovak Academy of Sciences

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