Proving Meromorphic Function Equality w/ Liouville's Theorem

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SUMMARY

The discussion centers on proving the equality of two meromorphic functions, \( r(z) \) and \( s(z) \), using Liouville's Theorem. It establishes that if \( |r(z)| \leq C|s(z)| \) for all complex numbers \( z \), then \( r(z) \) can be expressed as \( r(z) = C_1 s(z) \) for some complex constant \( C_1 \). The key insight is that the function \( r/s \) is meromorphic and bounded, leading to the conclusion that it must be constant due to Liouville's Theorem.

PREREQUISITES
  • Understanding of meromorphic functions
  • Familiarity with Liouville's Theorem
  • Knowledge of complex analysis concepts such as poles and bounded functions
  • Ability to manipulate complex inequalities
NEXT STEPS
  • Study the implications of Liouville's Theorem in complex analysis
  • Explore examples of meromorphic functions and their properties
  • Investigate the concept of removable singularities in complex functions
  • Learn about bounded functions in the context of complex variables
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This discussion is beneficial for mathematicians, particularly those specializing in complex analysis, as well as students seeking to deepen their understanding of meromorphic functions and Liouville's Theorem.

Dustinsfl
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Let $r(z)$ and $s(z)$ be meromorphic functions on the complex plane. Assume that there is a real number $C$ such that
$$
|r(z)|\leq C|s(z)|,\quad\text{for all complex numbers} \ z.
$$
Prove that $r(z) = C_1s(z)$, for some complex number $C_1$.

This intuitively makes sense. Basically the isolated singularities i.e. poles of r and s are removable when we have r/s such that r/s is a constant. Would the use of Liouville's theorem be used here?
 
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dwsmith said:
Let $r(z)$ and $s(z)$ be meromorphic functions on the complex plane. Assume that there is a real number $C$ such that
$$
|r(z)|\leq C|s(z)|,\quad\text{for all complex numbers} \ z.
$$
Prove that $r(z) = C_1s(z)$, for some complex number $C_1$.

This intuitively makes sense. Basically the isolated singularities i.e. poles of r and s are removable when we have r/s such that r/s is a constant. Would the use of Liouville's theorem be used here?
Yes, that is correct. The function r/s is meromorphic, and bounded by C. Therefore it has no poles, and Liouville's theorem shows that it must be constant.
 

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