Difference between revisions of "Measurable space"

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{{Refactor notice|grade=A*|msg=Lets get this measure theory stuff sorted. At least the skeleton
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* I can probably remove the old page... it doesn't say anything different.}}
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__TOC__
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==Definition==
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Given a [[set]], {{M|X}}, and a [[sigma-algebra|{{sigma|algebra}}]], {{M|\mathcal{A}\in\mathcal{P}(\mathcal{P}(X))}}<ref group="Note">More neatly written perhaps:
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* {{M|A\subseteq\mathcal{P}(X)}}</ref> then a ''measurable space''{{rMIAMRLS}}{{rAGTARAF}} is the [[tuple]]:
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* {{M|(X,\mathcal{A})}}
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This is not to be confused with a ''[[measure space]]'' which is a [[tuple|{{M|3}}-tuple]]: {{M|(X,\mathcal{A},\mu)}} where {{M|\mu}} is a [[measure]] on the ''measurable space'' {{M|(X,\mathcal{A})}}
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===[[Premeasurable space]]===
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{{:Premeasurable space/Definition}}
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==See also==
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* [[Pre-measurable space]]
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* [[Measure space]]
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** [[Measure]]
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** [[Measurable map]]
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==Notes==
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<references group="Note"/>
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==References==
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<references/>
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{{Definition|Measure Theory}}
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=OLD PAGE=
 
==Definition==
 
==Definition==
 
A ''measurable space''<ref name="MIM">Measures, Integrals and Martingales - Rene L. Schilling</ref> is a [[Tuple|tuple]] consisting of a set {{M|X}} and a [[Sigma-algebra|{{Sigma|algebra}}]] {{M|\mathcal{A} }}, which we denote:
 
A ''measurable space''<ref name="MIM">Measures, Integrals and Martingales - Rene L. Schilling</ref> is a [[Tuple|tuple]] consisting of a set {{M|X}} and a [[Sigma-algebra|{{Sigma|algebra}}]] {{M|\mathcal{A} }}, which we denote:

Latest revision as of 13:05, 2 February 2017

Grade: A*
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The message provided is:
Lets get this measure theory stuff sorted. At least the skeleton
  • I can probably remove the old page... it doesn't say anything different.

Definition

Given a set, [ilmath]X[/ilmath], and a [ilmath]\sigma[/ilmath]-algebra, [ilmath]\mathcal{A}\in\mathcal{P}(\mathcal{P}(X))[/ilmath][Note 1] then a measurable space[1][2] is the tuple:

  • [ilmath](X,\mathcal{A})[/ilmath]

This is not to be confused with a measure space which is a [ilmath]3[/ilmath]-tuple: [ilmath](X,\mathcal{A},\mu)[/ilmath] where [ilmath]\mu[/ilmath] is a measure on the measurable space [ilmath](X,\mathcal{A})[/ilmath]

Premeasurable space

  1. REDIRECT Pre-measurable space/Definition

See also

Notes

  1. More neatly written perhaps:
    • [ilmath]A\subseteq\mathcal{P}(X)[/ilmath]

References

  1. Measures, Integrals and Martingales - René L. Schilling
  2. A Guide To Advanced Real Analysis - Gerald B. Folland


OLD PAGE

Definition

A measurable space[1] is a tuple consisting of a set [ilmath]X[/ilmath] and a [ilmath]\sigma[/ilmath]-algebra [ilmath]\mathcal{A} [/ilmath], which we denote:

  • [ilmath](X,\mathcal{A})[/ilmath]

Pre-measurable space

A pre-measurable space[2] is a set [ilmath]X[/ilmath] coupled with an algebra, [ilmath]\mathcal{A} [/ilmath] (where [ilmath]\mathcal{A} [/ilmath] is NOT a [ilmath]\sigma[/ilmath]-algebra) which we denote as follows:

  • [ilmath](X,\mathcal{A})[/ilmath]

See also

References

  1. Measures, Integrals and Martingales - Rene L. Schilling
  2. Alec's own terminology, it's probably not in books because it's barely worth a footnote