Matsaev's theorem

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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.[1]

Matsaev's theorem

Let [math]\displaystyle{ f(z) }[/math] with [math]\displaystyle{ z=re^{i\theta} }[/math] be an entire function which is bounded from below as follows

[math]\displaystyle{ \log(|f(z)|)\geq -C\frac{r^{\rho}}{|\sin(\theta)|^s}, }[/math]

where

[math]\displaystyle{ C\gt 0,\quad \rho\gt 1\quad }[/math] and [math]\displaystyle{ \quad s\geq 0. }[/math]

Then [math]\displaystyle{ f }[/math] is of order [math]\displaystyle{ \rho }[/math] and has finite type.[2]

References

  1. Mazaew, Wladimir Igorewitsch (1960). "On the growth of entire functions that admit a certain estimate from below". Soviet Math. Dokl. 1: 548–552. 
  2. Kheyfits, A.I. (2013). "Growth of Schrödingerian Subharmonic Functions Admitting Certain Lower Bounds". Advances in Harmonic Analysis and Operator Theory. Operator Theory: Advances and Applications. 229. Basel: Birkhäuser. doi:10.1007/978-3-0348-0516-2_12.