Difference between revisions of "Cauchy sequence"

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(Definition)
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==Definition==
 
==Definition==
 
Given a [[Metric space|metric space]] {{M|(X,d)}} and a [[Sequence|sequence]] {{M|1=(x_n)_{n=1}^\infty\subseteq X}} is said to be a ''Cauchy sequence''<ref name="FA">Functional Analysis - George Bachman and Lawrence Narici</ref> if:
 
Given a [[Metric space|metric space]] {{M|(X,d)}} and a [[Sequence|sequence]] {{M|1=(x_n)_{n=1}^\infty\subseteq X}} is said to be a ''Cauchy sequence''<ref name="FA">Functional Analysis - George Bachman and Lawrence Narici</ref> if:
* {{M|\forall\epsilon > 0\exists N\in\mathbb{N}\forall n,m\in\mathbb{N}[n\ge m> N\implies d(x_m,x_n)<\epsilon]}}
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* {{M|\foryes is simply:
In words it is simply:
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* For any arbitrary distance apart, there exists a point such that any two points in the sequence after that point are within that arbitrary distance apart.
* For any arbitrary distance apart, there exists a point such that any two points in the sequence after that point are within that arbitrary distance apart.  
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==References==
 
==References==
 
<references/>
 
<references/>
  
 
{{Definition|Functional Analysis|Metric Space|Real Analysis}}
 
{{Definition|Functional Analysis|Metric Space|Real Analysis}}

Revision as of 07:45, 23 August 2015

Definition

Given a metric space [ilmath](X,d)[/ilmath] and a sequence [ilmath](x_n)_{n=1}^\infty\subseteq X[/ilmath] is said to be a Cauchy sequence[1] if:

  • {{M|\foryes is simply:
  • For any arbitrary distance apart, there exists a point such that any two points in the sequence after that point are within that arbitrary distance apart.

References

  1. Functional Analysis - George Bachman and Lawrence Narici