Banach measure

Banach measure

In mathematics, Banach measure in measure theory may mean a real-valued function on the algebra of "all" sets (for example, in the plane), by means of which a rigid, finitely additive area can be defined for every set, even when a set does not have a true geometric area. That is, this is a theoretical definition getting round the phenomenon of non-measurable sets. However, as the Vitali set shows, it cannot be countably additive.

The existence of Banach measures proves the impossibility of a Banach-Tarski paradox in two dimensions.

The concept of "Banach measure" is to be distinguished from the idea of a measure taking values in a Banach space, for example in the theory of spectral measures.

External links

* [http://www-groups.dcs.st-and.ac.uk/~history/Mathematicians/Banach.html Stefan Banach bio]


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