Friday, 1 May 2015

Linguistic Note 8 Vector Space



8

Vector Space


    TANAKA Akio

1
Additive group becomes vector space on field K in below condition.
Vector space defines scalar multiplication that is au  V in element of K and element u of V.
In vector space, arbitrary element of K and V has distributive law, associative law and identity element.

2
Vector space makes functional space in below condition.
Map from set M to field K       K valued function.
All the sets of K valued function on M      F ( MK )
Definition of addition between two functions f and g      f, g  F ( MK )     ( f + g ) ( u ) = f ( u ) + g ( u )
Definition of scalar multiplication af between element a on K.     ( af ) ( ) = af ( u )
Functional space F ( MK ) becomes vector space.
When set M is M = {1, … , n }, F ( MK ) is numerical vector space.

3
K–vector space Vhas linear map φV → W in below condition.
Arbitrary u, v  V and arbitrary a  K have distributive law and associative law.
Kernel of linear map     Ker (φ) = { u  V | φ u ) = 0 }
Image of linear map      Im (φ) = { φ u ) |  u  V  }

4
Linear map φ is expressed by matrix.

5
When V and W are finitely dimensional vector spaces, dimension of linear map is below.
Dim ( V ) = dim ( Ker ( φ ) + dim ( Im ( φ ) )

[Note]
Exact sequence on additive group may be helpful for connection of words.

[References]
<On Lineation>
<On connection> 

Tokyo July 27, 2007

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