Matsaev's theorem is a theorem from complex analysis, which characterizes the order and type of an entire function. The theorem was proven in 1960 by Vladimir Igorevich Matsaev.
Matsaev's theorem Let f ( z ) {\displaystyle f(z)} with z = r e i θ {\displaystyle z=re^{i\theta }} be an entire function which is bounded from below as follows
log ( | f ( z ) | ) ≥ − C r ρ | sin ( θ ) | s , {\displaystyle \log(|f(z)|)\geq -C{\frac {r^{\rho }}{|\sin(\theta )|^{s}}},}
where
C > 0 , ρ > 1 {\displaystyle C>0,\quad \rho >1\quad } and s ≥ 0. {\displaystyle \quad s\geq 0.}
Then f {\displaystyle f} is of order ρ {\displaystyle \rho } and has finite type.
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