文摘
The old result due to [Ozaki, S.: On the theory of multivalent functions II. Sci. Rep. Tokyo Bunrika Daigaku Sect. A, 45–87 (1941)], says that if \(f\left( z \right) = {z^p} + \sum\nolimits_{n = p + 1}^\infty {{a_n}} {z^n}\) anzn is analytic in a convex domain D and for some real α we have Re{exp(iα)f(p)(z) >} 0 in D, then f(z) is at most p-valent in D. In this paper, we consider similar problems in the unit disc D = {z ∈ C: |z| < 1}.