Riemann integral is zero for certain sets

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SUMMARY

The Riemann integral of a function defined on a closed Jordan domain within the set ##\pi=\{ x\in\mathbb{R}^n \;|\; x=(x_1,...,x_{n-1}, 0) \}## is zero if the function is Riemann integrable. Specifically, for any closed Jordan domain ##E \subset \pi## and a Riemann integrable function ##f: E \rightarrow \mathbb{R}##, the integral satisfies ##\int_{E} f(x) dV = 0##. The proof involves demonstrating that for any given ##\varepsilon > 0##, there exist upper and lower sums ##U## and ##L## such that ##-\varepsilon < L < U < \varepsilon##.

PREREQUISITES
  • Understanding of Riemann integrability and its criteria.
  • Familiarity with closed Jordan domains in mathematical analysis.
  • Knowledge of upper and lower sums in the context of integration.
  • Basic concepts of measure theory related to sets in ##\mathbb{R}^n##.
NEXT STEPS
  • Study the properties of closed Jordan domains in detail.
  • Learn about the criteria for Riemann integrability and its implications.
  • Explore the concept of upper and lower sums in Riemann integration.
  • Investigate measure theory fundamentals, particularly in ##\mathbb{R}^n##.
USEFUL FOR

Mathematics students, educators, and researchers focusing on real analysis, particularly those studying integration theory and its applications in higher dimensions.

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Homework Statement


The question is:

Let ##\pi=\left \{ x\in\mathbb{R}^n\;|\;x=(x_1,...,x_{n-1}, 0) \right \}##. Prove that if ##E\subset\pi## is a closed Jordan domain, and ##f:E\rightarrow\mathbb{R}## is Riemann integrable, then ##\int_{E}f(x)dV=0##.




Homework Equations



n/a

The Attempt at a Solution


(How to relate the condition it's Riemann integrable to the value is ##0##? The textbook I use define ##f## is integrable on ##E## iff ##\;\;\;\;(L)\int_{E}fdV=(U)\int_{E}fdV##)
 
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What is the definition of "closed Jordan domain"?

Regardless of what the answer to that is, the strategy here should definitely be to prove that given ##\varepsilon>0##, there's an upper sum U and a lower sum L such that ##-\varepsilon<L<U<\varepsilon##. You may want to try this for an especially simple choice of E and f before you try the general case.
 
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