Does the Maximum Principle Apply to Harmonic Functions in Bounded Regions?

In summary, bounds for analytic functions refer to upper and lower limits on the values that an analytic function can take on within a given domain. These bounds are determined through various techniques such as the Cauchy-Schwarz inequality, the maximum modulus theorem, and the Harnack's inequality. They are important in understanding the behavior and properties of the function, and can change depending on the domain and techniques used. In real-world applications, bounds for analytic functions are useful in predicting and analyzing the behavior of systems, optimizing designs, and solving differential equations.
  • #1
haya
15
0

Homework Statement




Let u(x; y) be real, nonconstant, and continuous in a closed
bounded region R. Let u(x; y) be harmonic in the interior of R. Prove that
the maximum and minimum value of u(x; y) in this region occurs on the boundary.



Homework Equations



the theorem said that( a function analtic in bounded domain and continuous up to and including its boundry attains its maximum modlus on the boundry

The Attempt at a Solution



can i suppose that u(x;y) is nonzero ?
 
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  • #2
Is R connected?
If so, this is just the maximum principle
 

Related to Does the Maximum Principle Apply to Harmonic Functions in Bounded Regions?

1. What are bounds for analytic functions?

Bounds for analytic functions refer to upper and lower limits on the values that an analytic function can take on within a given domain. These bounds are often expressed in terms of a maximum and minimum value, and provide important information about the behavior of the function.

2. How are bounds for analytic functions determined?

The bounds for an analytic function are determined through various techniques such as the Cauchy-Schwarz inequality, the maximum modulus theorem, and the Harnack's inequality. These methods involve analyzing the behavior of the function and its derivatives within a given domain to determine the maximum and minimum values it can take on.

3. Why are bounds for analytic functions important?

Bounds for analytic functions are important because they provide valuable information about the behavior and properties of the function. They can help in determining the convergence and divergence of series, identifying critical points and extrema, and understanding the overall behavior of the function within a given domain.

4. Can bounds for analytic functions change?

Yes, bounds for analytic functions can change depending on the domain of the function and the techniques used to determine them. For example, if the domain is expanded or restricted, the bounds may change accordingly. Additionally, different techniques may lead to different bounds for the same function.

5. How are bounds for analytic functions useful in real-world applications?

Bounds for analytic functions have various real-world applications, particularly in fields such as engineering, physics, and economics. They can help in predicting and analyzing the behavior of systems, optimizing designs, and making accurate predictions based on numerical data. Additionally, they are used in solving differential equations and modeling complex systems.

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