Outer measure: Difference between revisions

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Let <math> X </math> be a nonempty set. An outer measure on the set <math> X </math> is a function <math> \mu^* : 2^X \to [0, \infty]</math> such that
Let <math> X </math> be a nonempty set. An outer measure <ref name="Folland">[Gerald B. Folland, ''Real Analysis: Modern Techniques and Their Applications, second edition'', Chapter 1.]</ref> on the set <math> X </math> is a function <math> \mu^* : 2^X \to [0, \infty]</math> such that
* <math> \mu^* ( \emptyset) = 0 </math>
* <math> \mu^* ( \emptyset) = 0 </math>
* <math> \mu^*(A) \leq \mu^*(B)</math> if <math> A \subseteq B</math>
* <math> \mu^*(A) \leq \mu^*(B)</math> if <math> A \subseteq B</math>
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==References==
==References==
<references>
<ref name="Folland">[Gerald B. Folland, ''Real Analysis: Modern Techniques and Their Applications, second edition'', Chapter 1.]</ref>

Revision as of 14:25, 20 October 2020

Let be a nonempty set. An outer measure [1] on the set is a function such that

  • if


References

  1. [Gerald B. Folland, Real Analysis: Modern Techniques and Their Applications, second edition, Chapter 1.]