Uniform integrability under continuous functions

In summary, uniform integrability under continuous functions is a mathematical concept where a set of integrable functions converge uniformly to a limit function. This is different from pointwise integrability, which only requires the functions to converge at each point independently. Uniform integrability is important in mathematics for studying the behavior of functions as the independent variable approaches a certain value, and it can also be applied in real-world situations such as in physics, engineering, economics, and finance. However, there are limitations to uniform integrability, such as the requirement for continuous functions and uniform convergence.
  • #1
jk_zhengli
6
0
Let X be a uniform integrable function, and g be a continuous function. Is is true that g(X) is UI?

I don't think g(X) is UI, but I have trouble finding counter examples.

Thanks.
 
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  • #2
This statement is true whenever \supp g (You can prove this with Heine Borel) or the range of {X_n} is compact.
Since now you have the compactness relaxed, you can pursue that direction.

Also, the foundation of this question is more towards Intro to Meas. Theory, you may consider re-post in the right domain.
 
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1. What is uniform integrability under continuous functions?

Uniform integrability under continuous functions is a mathematical concept that refers to a set of integrable functions that converge uniformly to a limit function. This means that as the independent variable approaches a certain value, the values of the functions also approach the value of the limit function at the same rate.

2. How is uniform integrability different from pointwise integrability?

Uniform integrability is different from pointwise integrability in that uniform integrability requires a set of functions to converge uniformly to a limit function, while pointwise integrability only requires the functions to converge at each point independently.

3. Why is uniform integrability important in mathematics?

Uniform integrability is important in mathematics because it allows for the study of the behavior of a set of integrable functions as the independent variable approaches a certain value. This is useful in many areas of mathematics, including calculus, analysis, and probability theory.

4. How can uniform integrability be applied in real-world situations?

Uniform integrability can be applied in real-world situations, such as in physics and engineering, where it is used to study the behavior of physical systems as variables approach certain values. It can also be used in economics and finance to analyze the behavior of financial markets and investments.

5. Are there any limitations to uniform integrability under continuous functions?

Yes, there are limitations to uniform integrability under continuous functions. For example, the functions must be continuous and the limit function must also be continuous. Additionally, the convergence of the functions must be uniform, which may not always be the case for all sets of functions.

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