What are the entire functions with bounded modulus on the complex plane?

  • Thread starter Thread starter g1990
  • Start date Start date
  • Tags Tags
    Maximum Modulus
Click For Summary
SUMMARY

The discussion centers on identifying entire functions f(z) that satisfy the condition |zf(z)| ≤ 1 for all z in the complex plane. According to the maximum modulus principle, the only entire functions that are bounded must be constant functions. The analysis concludes that the only function meeting the criteria is f(z) = 0, as any non-zero constant would violate the boundedness condition when multiplied by z.

PREREQUISITES
  • Understanding of entire functions in complex analysis
  • Familiarity with the maximum modulus principle
  • Knowledge of complex function properties
  • Basic concepts of boundedness in the context of complex functions
NEXT STEPS
  • Study the maximum modulus principle in detail
  • Explore the properties of entire functions and their implications
  • Investigate the implications of boundedness in complex analysis
  • Learn about Liouville's theorem and its applications
USEFUL FOR

Students and professionals in mathematics, particularly those focusing on complex analysis, as well as anyone interested in the properties of entire functions and their boundedness.

g1990
Messages
35
Reaction score
0

Homework Statement


Find all entire functions f(z) with the property that |zf(z)|<=1 for all z in C


Homework Equations


The maximum modulus principle says that the only functions that are entire and bounded are constant functions.


The Attempt at a Solution


I know that if f(z) is entire, then zf(z) is also entire. Thus, if it's modulus is bounded on C, then it must be constant. Thus, zf(z)=c, so that f(z)=c/z where c is a constant. But then, f is not entire. Am I doing something wrong? Or is the only function that satisfies this property zero?
 
Physics news on Phys.org
That looks right to me. Only f(z)=0 works.
 

Similar threads

  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 8 ·
Replies
8
Views
2K
Replies
2
Views
1K
  • · Replies 3 ·
Replies
3
Views
5K
Replies
7
Views
3K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 2 ·
Replies
2
Views
4K