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JOURNALS // Vestnik of Saint Petersburg University. Mathematics. Mechanics. Astronomy // Archive

Vestnik of Saint Petersburg University. Mathematics. Mechanics. Astronomy, 2025 Volume 12, Issue 2, Pages 325–336 (Mi vspua358)

MATHEMATICS

A $q$-generalization of class $R$

S. Vermaa, R. Kumarb, J. Sokolc, S. Singhd

a University of Jammu, Jammu-180006, Jammu and Kashmir, India
b DAV University, Jalandhar-144012, Punjab, India
c College of Natural Sciences, University of Rzeszow, 1, ul. Prof. Pigonia, Rzeszow, 35-310, Poland
d Sant Longowal Institute of Engineering and Technology, Longowal-148106, Punjab, India

Abstract: For $0 < q < 1$, we define a new class $R_q$ of analytic functions using $q$-difference operator, which is a $q$-analogue of class $R$. We prove that the class $R$ is properly contained in $R_q$ and find a sharp lower bound for the real part of $D_q f$, where $f \in R_q$. We investigate certain convolution properties of functions in the class $R_q$ including that the class $R_q$ is closed under convolution for a definite range of $q$. The findings of the present manuscript essentially generalizes some well-known results in the literature.

Keywords: convolution, q-derivative, q-starlike.

UDC: 517.54

MSC: 30C45; 30C50

Received: 15.10.2023
Revised: 25.09.2024
Accepted: 21.11.2024



© Steklov Math. Inst. of RAS, 2025