A class of univalent functions with real coefficients

Abstract

In this paper we study class ${\mathcal{S}}^{+}$ of univalent functions $f$ such that $\frac{z}{f(z)}$ has real and positive coefficients. For such functions we give estimates of the Fekete-Szegő functional and sharp estimates of their initial coefficients and logarithmic coefficients. Also, we present necessary and sufficient conditions for $f\in {\mathcal{S}}^{+}$ to be starlike of order $1/2$.