sub-probability measure

In the mathematical theory of probability and measure, a sub-probability measure is a measure that is closely related to probability measures. While probability measures always assign the value 1 to the underlying set, sub-probability measures assign a value lesser than or equal to 1 to the underlying set.

Definition

Let \mu be a measure on the measurable space (X, \mathcal A) .

Then \mu is called a sub-probability measure if \mu(X) \leq 1 .

Properties

In measure theory, the following implications hold between measures:

\text{probability} \implies \text{sub-probability} \implies \text{finite} \implies \sigma\text{-finite}

So every probability measure is a sub-probability measure, but the converse is not true. Also every sub-probability measure is a finite measure and a σ-finite measure, but the converse is again not true.

See also

References

{{cite book |last1=Klenke |first1=Achim |year=2008 |title=Probability Theory |location=Berlin |publisher=Springer |doi=10.1007/978-1-84800-048-3 |isbn=978-1-84800-047-6 |page=247}}

{{cite book |last1=Kallenberg |first1=Olav |author-link1=Olav Kallenberg |year=2017 |title=Random Measures, Theory and Applications|location= Switzerland |publisher=Springer |page=30|doi= 10.1007/978-3-319-41598-7|isbn=978-3-319-41596-3}}

{{Measure theory}}

Category:Probability theory

Category:Measures (measure theory)