How is √2 μ Interpreted Geometrically?

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Discussion Overview

The discussion revolves around the geometric interpretation of the measure √2 μ, particularly in the context of real analysis. Participants are exploring how this measure relates to integrals and geometric concepts such as area.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant seeks help interpreting the measure √2 μ geometrically, indicating it is part of a real analysis problem.
  • Another participant questions what the measure μ represents, suggesting it is the unique positive regular measure on B(R²) related to integrals over compactly supported continuous functions.
  • A later reply proposes that the question may be approached intuitively by considering the Riemann integral, noting that if a function is Riemann integrable, the integrals with respect to the measures μ and area (dA) yield equivalent results.
  • This participant suggests that using a simple function, such as f=1, illustrates that the integral computes area, and that the measure √2 μ scales this area by √2, raising questions about the geometric implications of this scaling.

Areas of Agreement / Disagreement

Participants express varying levels of understanding and approaches to interpreting the measure, with no consensus reached on a definitive geometric interpretation.

Contextual Notes

There are unresolved aspects regarding the specific properties of the measure μ and its relationship to the Riemann integral, as well as the implications of scaling by √2.

Juliayaho
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This is part 2 of a question... I already solved part 1 but I can't seem to be able to solve this one.
Interpret the measure √2 μ geometrically?

Any ideas... This is from real analysis class

Thanks in advance!
 
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Re: Measure... Geometrically?

Juliayaho said:
This is part 2 of a question... I already solved part 1 but I can't seem to be able to solve this one.
Interpret the measure √2 μ geometrically?

Any ideas... This is from real analysis class

Thanks in advance!

What is [math]\displaystyle \mu [/math] representing?
 
Re: Measure... Geometrically?

The unique positive regular measure on B(R^2) such that for all f in C_c(R^2) λf= ∫_R^2 f dµ

- - - Updated - - -

Prove It said:
What is [math]\displaystyle \mu [/math] representing?

The unique positive regular measure on B(R^2) such that for all f in C_c(R^2) λf= ∫_R^2 f dµ

- - - Updated - - -

Juliayaho said:
The unique positive regular measure on B(R^2) such that for all f in C_c(R^2) λf= ∫_R^2 f dµ

- - - Updated - - -
The unique positive regular measure on B(R^2) such that for all f in C_c(R^2) λf= ∫_R^2 f dµ

λf=∫(from R to Riemann) f(tt)dt for all f in C_c(R^2).
 
Re: Measure... Geometrically?

I could be wrong, but it seems to me that this question could be answered much more easily (that is, intuitively) by thinking about the corresponding Riemann integral. It's a fact that if the function is Riemann integrable, then
$$\int_{ \mathbb{R}^{2}} f \, dA = \int_{ \mathbb{R}^{2}} f \, d\mu.$$
So take an example, and make $f$ really simple, say $f=1$. Then your integral is simply computing area. Your new measure, $\sqrt{2} \mu$, simply multiplies your area by $\sqrt{2}$, since constants pull out of integrals (at least, they pull out of Riemann and Lebesgue integrals). What is going on geometrically for that to happen?
 

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