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Difference between revisions of "Arithmetic space"

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m (fixing spaces)
m (fixing dots)
 
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$$  
 
$$  
( x _ {1} \dots x _ {n} ) + ( x _ {1}  ^  \prime \dots x _ {n}  ^  \prime  )
+
( x _ {1}, \dots, x _ {n} ) + ( x _ {1}  ^  \prime , \dots, x _ {n}  ^  \prime  )
  =  ( x _ {1} + x _ {1}  ^  \prime \dots x _ {n} + x _ {n}  ^  \prime  );
+
  =  ( x _ {1} + x _ {1}  ^  \prime , \dots, x _ {n} + x _ {n}  ^  \prime  );
 
$$
 
$$
  
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$$  
 
$$  
\lambda ( x _ {1} \dots x _ {n} )  = \  
+
\lambda ( x _ {1}, \dots, x _ {n} )  = \  
( \lambda x _ {1} \dots \lambda x _ {n} ).
+
( \lambda x _ {1}, \dots, \lambda x _ {n} ).
 
$$
 
$$
  
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$$  
 
$$  
I  =  \{ {( x _ {1} \dots x _ {n} ) \in \mathbf R  ^ {n} } : {
+
I  =  \{ {( x _ {1}, \dots, x _ {n} ) \in \mathbf R  ^ {n} } : {
a _ {i} < x _ {i} < b _ {i} , i = 1 \dots n } \}
+
a _ {i} < x _ {i} < b _ {i} , i = 1, \dots, n } \}
 
,
 
,
 
$$
 
$$
  
where the numbers  $  a _ {1} \dots a _ {n} $
+
where the numbers  $  a _ {1}, \dots, a _ {n} $
and  $  b _ {1} \dots b _ {n} $
+
and  $  b _ {1}, \dots, b _ {n} $
 
are given.
 
are given.
  
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$$
 
$$
  
where  $  x = ( x _ {1} \dots x _ {n} ) \in \mathbf R  ^ {n} $,  
+
where  $  x = ( x _ {1}, \dots, x _ {n} ) \in \mathbf R  ^ {n} $,  
 
and is a Euclidean space with respect to the scalar product
 
and is a Euclidean space with respect to the scalar product
  
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$$
 
$$
  
where  $  x = ( x _ {1} \dots x _ {n} ) , y = ( y _ {1} \dots y _ {n} ) \in \mathbf R  ^ {n} $.
+
where  $  x = ( x _ {1}, \dots, x _ {n} ) , y = ( y _ {1}, \dots, y _ {n} ) \in \mathbf R  ^ {n} $.

Latest revision as of 08:25, 4 March 2022


number space, coordinate space, real $ n $-space

A Cartesian power $ \mathbf R ^ {n} $ of the set of real numbers $ \mathbf R $ having the structure of a linear topological space. The addition operation is here defined by the formula:

$$ ( x _ {1}, \dots, x _ {n} ) + ( x _ {1} ^ \prime , \dots, x _ {n} ^ \prime ) = ( x _ {1} + x _ {1} ^ \prime , \dots, x _ {n} + x _ {n} ^ \prime ); $$

while multiplication by a number $ \lambda \in \mathbf R $ is defined by the formula

$$ \lambda ( x _ {1}, \dots, x _ {n} ) = \ ( \lambda x _ {1}, \dots, \lambda x _ {n} ). $$

The topology in $ \mathbf R ^ {n} $ is the topology of the direct product of $ n $ copies of $ \mathbf R $; its base is formed by open $ n $-dimensional parallelepiped:

$$ I = \{ {( x _ {1}, \dots, x _ {n} ) \in \mathbf R ^ {n} } : { a _ {i} < x _ {i} < b _ {i} , i = 1, \dots, n } \} , $$

where the numbers $ a _ {1}, \dots, a _ {n} $ and $ b _ {1}, \dots, b _ {n} $ are given.

The real $ n $-space $ \mathbf R ^ {n} $ is also a normed space with respect to the norm

$$ \| x \| = \sqrt {x _ {1} ^ {2} + \dots +x _ {n} ^ {2} } , $$

where $ x = ( x _ {1}, \dots, x _ {n} ) \in \mathbf R ^ {n} $, and is a Euclidean space with respect to the scalar product

$$ \langle x, y \rangle = \sum _ {i=1 } ^ { n } x _ {i} y _ {i} , $$

where $ x = ( x _ {1}, \dots, x _ {n} ) , y = ( y _ {1}, \dots, y _ {n} ) \in \mathbf R ^ {n} $.

How to Cite This Entry:
Arithmetic space. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Arithmetic_space&oldid=52178
This article was adapted from an original article by I.V. Dolgachev (originator), which appeared in Encyclopedia of Mathematics - ISBN 1402006098. See original article