Coefficient estimates for the class of q-starlike functions

Abstract

By employing the $q$-difference operator, various classes of $q$-extensions of starlike functions have emerged from many different viewpoints and perspectives. Ruscheweyh's work unified these $q$-extensions with convolution operations. Inspired by prior research, this paper delves into the class of $q$-starlike functions defined via convolution. First, we provide comprehensive analysis of its Taylor coefficients by using the Carath\'eodory-Toeplitz Theorem and its corollaries. Precise upper bounds for the initial few coefficients are obtained for real $q\in(0,1)$. Furthermore, we analyze both Hankel and Toeplitz determinants by using the foundational results. Second, we establish the upper bounds of its coefficients with the application of Parseval's theorem for $q$-starlike functions when $q$ is a complex number.