RUS  ENG
Full version
JOURNALS // Matematicheskii Sbornik // Archive

Mat. Sb. (N.S.), 1971 Volume 84(126), Number 2, Pages 273–289 (Mi sm3070)

Some estimates in the class of analytic functions of bounded type

V. P. Vazhdaev, S. A. Gel'fer


Abstract: We consider the class $A_M$ of functions regular in the disk $|\zeta|<1$ which for any $r$, $0\leqslant r<1$, satisfy the condition
$$ \int_0^{2\pi}\ln^+|f(re^{i\theta})|\,d\theta\leqslant2\pi M, $$
where $M$ does not depend on the function. Using a parametric representation of this class, the authors find exact estimates of the mean arithmetic value and the mean geometric value of the modulus of the function at equally spaced points of the circumference, estimates of the moduli and arguments of the function, the moduli of the derivatives and other values for the class $A_M$ and certain of its subclasses.
The solution of these problems is based on variation formulas introduced earlier by one of the authors (RZhMat., 1967, 11B99).
Bibliography: 14 titles.

UDC: 517.53

MSC: 30A76

Received: 23.02.1970


 English version:
Mathematics of the USSR-Sbornik, 1971, 13:2, 267–284

Bibliographic databases:


© Steklov Math. Inst. of RAS, 2024