Difference between revisions of "Norm/Heading"

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{{Infobox
 
{{Infobox
 
|title=Norm
 
|title=Norm
|above=<span style="font-size:2em;">{{M|\Vert\cdot\Vert:V\rightarrow\mathbb{R} }}</span><br/>Where {{M|V}} is a [[vector space]] over the [[field]] {{M|\mathbb{R} }} or {{M|\mathbb{C} }}
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|above=<span style="font-size:2em;">{{M|\Vert\cdot\Vert:V\rightarrow\mathbb{R}_{\ge 0} }}</span><br/>Where {{M|V}} is a [[vector space]] over the [[field]] {{M|\mathbb{R} }} or {{M|\mathbb{C} }}
 
|header1=[[subtypes of topological spaces|relation to other topological spaces]]
 
|header1=[[subtypes of topological spaces|relation to other topological spaces]]
 
|label1=''is a''
 
|label1=''is a''

Latest revision as of 19:28, 25 January 2016

Norm
[ilmath]\Vert\cdot\Vert:V\rightarrow\mathbb{R}_{\ge 0} [/ilmath]
Where [ilmath]V[/ilmath] is a vector space over the field [ilmath]\mathbb{R} [/ilmath] or [ilmath]\mathbb{C} [/ilmath]
relation to other topological spaces
is a
contains all
Related objects
Induced metric
  • [ilmath]d_{\Vert\cdot\Vert}:V\times V\rightarrow\mathbb{R}_{\ge 0}[/ilmath]
  • [ilmath]d_{\Vert\cdot\Vert}:(x,y)\mapsto\Vert x-y\Vert[/ilmath]
Induced by inner product
  • [ilmath]\Vert\cdot\Vert_{\langle\cdot,\cdot\rangle}:V\rightarrow\mathbb{R}_{\ge 0}[/ilmath]
  • [ilmath]\Vert\cdot\Vert_{\langle\cdot,\cdot\rangle}:x\mapsto\sqrt{\langle x,x\rangle}[/ilmath]
A norm is a an abstraction of the notion of the "length of a vector". Every norm is a metric and every inner product is a norm (see Subtypes of topological spaces for more information), thus every normed vector space is a topological space to, so all the topology theorems apply. Norms are especially useful in functional analysis and also for differentiation.