Measure of Reals: Countable or Uncountable?

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SUMMARY

The discussion centers on the measure of real numbers in the context of measure theory, specifically addressing the misconception that an uncountable union of singletons, each with zero measure, can be treated as having a total measure of zero. It is established that the measure of a disjoint union is the sum of the measures of its components, which only applies to countable sets. The complexity of defining the sum of an uncountable set of numbers is highlighted, emphasizing the need for a deeper understanding of measure theory principles.

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  • Familiarity with the properties of measure, particularly regarding countable and uncountable sets
  • Knowledge of singleton sets and their measures
  • Basic mathematical analysis skills
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cragar
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I was reading a little about measure theory, and the measure of a singleton is zero.
So why couldn't we just describe the reals as an uncountable number of singletons which each have zero measure and then union all of these singletons.
Maybe the union only works for countable sets when talking about measure.
 
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You are trying to apply the principle that the measure of a disjoint union is the sum of the measures of the components, right?

How do you define the sum of an uncountable set of numbers?
 

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