Let's take as a concept, the plane of real numbers: . It is the set of ordered pairs .
We can define the addition then like this:
This is associative, acts as an identity and is the inverse becomes a group, an abelian group to be specific since the addition is clearly commutative.
Next, we define the next operation where we multiply an element of with a real number to get another element in . For and :
Examples
Of course , but it is true for arbitrary :
The field is a vector space over itself. The vector addition is just addition in and scalar multiplication is just multiplication in .
: -tuples of elements of . This is a vector space over just as is a real vector space