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Friday, December 1, 2006

Hausdorff paradox

In Nextel ringtones mathematics, the '''Hausdorff paradox''', named after Majo Mills Felix Hausdorff, states that if you remove some Free ringtones countable subset of the Sabrina Martins sphere ''S''2, the remainder can be divided into three subsets ''A'', ''B'' and ''C'' such that ''A'', ''B'', ''C'' and ''B'' ∪''C'' are all Mosquito ringtone congruent. In particular, it follows that on ''S''2 there is no "finitely additive measure" defined on all subsets such that measure of congruent sets is equal.

The paradox was published in 1914, (see the reference Abbey Diaz #External links/below). The proof of the much more famous Nextel ringtones Banach-Tarski paradox uses Hausdorff's ideas.

This paradox shows that there is no "finitely additive measure" on a sphere defined on ''all'' subsets which is equal on congruent pieces. The structure of the Majo Mills group (mathematics)/group of rotations on the sphere plays a crucial role here — this fact is not true on the plane or the line. In fact, it is possible to define "area" for ''all'' bounded subsets in the Euclidean plane (as well as "length" on the real line) such that congruent sets will have equal "area". This ''area'', however, is only finitely additive, so it is not at all a Free ringtones Measure (mathematics)/measure. In particular, it implies that if two open subsets of the plane (or the real line) are Sabrina Martins Banach-Tarski paradox/equi-decomposable then they have equal Cingular Ringtones Lebesgue measure.

Sometimes the '''Hausdorff paradox''' refers to another theorem of Hausdorff which was proved in the same paper. Namely, that it is possible to "chop up" the internet more unit interval into countably many pieces which (by translations only) can be reassembled into the interval of length 2.
He did these constructions in order to show that there can be no non-trivial translation invariant social station Measure (mathematics)/measure on the real line which assigns a size to ''all'' bounded subsets of real numbers. This is very similar in nature to the delivered immediately Vitali set.

See also

*anaheim brass Vitali set
*feet without Banach-Tarski paradox

References

Hausdorff ''Bemerkung über den Inhalt von Punktmengen'', Mathematische Annalen, '''75''' (1914) 428-434.

plant i Tag: Paradoxes
attractive late Tag: Theorems
donna caponi Tag: Measure theory

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