Abstract:
We define $\mathscr V(\alpha,\beta)$ ($alpha<1$ and $\beta>1$), the new subclass of analytic functions with bounded positive real part, $$
\mathscr V(\alpha,\beta)^=\Bigl\{f\in\mathscr A\colon\alpha<\operatorname{Re}\Bigl\{\Bigl(\frac z{f(z)}\Bigr)^2f'(z)\Bigr\}<\beta\Bigr\},
$$
and study some properties of $\mathscr V(\alpha,\beta)$. We also study the class $\mathscr U(\gamma)$ ($\gamma>0$):
$$
\mathscr U(\gamma):=\Bigl\{f\in\mathscr A\colon\Bigl|\Bigl(\frac z{f(z)}\Bigr)^2f'(z)-1\Bigr|<\gamma\Bigr\},
$$
where $\mathscr A$ is the class of normalized functions.
Keywords:analytic function, subordination, bounded positive real part, Fekete–Szegö problem.