Sort:
Open Access Research Article Issue
Regions of variability for generalized Janowski functions
AIMS Mathematics 2026, 11(2): 3499-3511
Published: 05 February 2026
Abstract PDF (251.1 KB) Collect
Downloads:2

Let r C , s [ 1 , 0 ), 0 α < 1. Then, Q [ r , s , α ] stands for the set of analytic functions q that is within the open unit disk E, with q ( 0 ) = 1 , and satisfies the explicit representation

q ( ζ ) = 1 + ( ( 1 α ) r + α s ) χ ( ζ ) 1 + s χ ( ζ ) ,

where χ ( 0 ) = 0 and $ \left \vert \chi \left(\zeta \right)\right \vert < 1. I n t h i s a r t i c l e , w e f i n d t h e r e g i o n s o f v a r i a b i l i t y W_{\lambda }\left(\zeta _{0}, r, s, \alpha \right) f o r \int \limits_{0}^{z_{0}}q\left(\rho \right) d\rho \ w h e n q r a n g e s o v e r t h e c l a s s \mathcal{Q}_{\lambda }\left[r, s, \alpha \right] $ defined as

Q λ [ r , s , α ] = { q Q [ r , s , α ] : q ( 0 ) = ( ( 1 α ) ( r s ) ) λ }

for any fixed ζ 0 E and λ E ¯ . As a corollary, the region of variability appears for the alternate sets of parameters as well.

Open Access Research Article Issue
Geometric perspectives on the variability of spiralike functions with respect to a boundary point in relation to Janowski functions
AIMS Mathematics 2025, 10(6): 13006-13024
Published: 06 June 2025
Abstract PDF (279.4 KB) Collect
Downloads:30

Investigating the variability domain in the geometric function theory yields profound insights into the behavior of geometric functions, thereby facilitating the examination of extremal problems and the derivation of bounds and inequalities. While the previous literature has examined similar classes, our approach offers significant advantages through a more generalized framework. Our study considers normalized analytic functions with specific positivity conditions which involve complex parameters. This investigation extends a previous work by analyzing a broader set of non-vanishing analytic functions. Unlike earlier studies that focused on specific parameter values, our approach allows for wider applications across multiple subclasses through the incorporation of additional parameters. We aim to determine the variability domain for the logarithm of these functions at fixed points within the unit disk as the functions range over a particular class defined by the specific parameter constraints. This generalized approach unifies several known results and provides a comprehensive framework to solve previously intractable boundary problems in the geometric function theory.

Total 2