On a Fekete–Szegö Problem Associated with Generalized Telephone Numbers

Abstract

One of the important problems regarding coefficients of analytical functions (i.e., Fekete–Szegö inequality) was raised by Fekete and Szegö in 1933. The results of this research are dedicated to determine upper coefficient estimates and the Fekete–Szegö problem in the class WΣ(δ,λ;ϑ), which is defined by generalized telephone numbers. We also indicate some specific conditions and consequences of results found by us.

Keywords

• bi-univalent function
• holormorphic function
• upper bounds
• telephone numbers
• Fekete–Szegö problem