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JOURNALS // Zapiski Nauchnykh Seminarov POMI // Archive

Zap. Nauchn. Sem. POMI, 2001 Volume 276, Pages 41–51 (Mi znsl1411)

This article is cited in 1 paper

On the regions of values of systems $\{f(z_0),f'(z_0),c_2\}$ and $\{f(r),f'(r),f(z_0)\}$ in the class of typically real functions

E. G. Goluzina

St. Petersburg Department of V. A. Steklov Institute of Mathematics, Russian Academy of Sciences

Abstract: Let $T$ be the class of functions $f(z)$ having the following properties: these functions are regular and typically real in the disk $|z|<1$ and have the expansions $f(z)=z+c_2z^2+c_3z^3+\dotsb$. We give algebraic and geometric characterizations of regions of values for the functionals in the class $T$ mentioned in the title. In the same class of functions, we find regions of values for $f'(z_0)$ with fixed $c_2$ and $f(z_0)$ and for $f(z_0)$ with fixed $f(r)$ and $f'(r)$.

UDC: 517.54

Received: 19.02.2001


 English version:
Journal of Mathematical Sciences (New York), 2003, 118:1, 4753–4759

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