Real Numbers form Vector Space

Theorem

The set of real numbers $\R$, with the operations of addition and multiplication, forms a vector space.

Proof

Let the Field of Real Numbers be denoted $\left({\R, +, \times}\right)$.

From Real Vector Space is Vector Space, we have that $\left({\R^n, +, \cdot}\right)$ is a vector space, where:

$\mathbf a + \mathbf b = \left({a_1 + b_1, a_2 + b_2, \ldots, a_n + b_n}\right)$

$\lambda \cdot \mathbf a = \left({\lambda \times a_1, \lambda \times a_2, \ldots, \lambda \times a_n}\right)$

where:

$\mathbf a, \mathbf b \in \R^n$

$\lambda \in \R$

$\mathbf a = \left({a_1, a_2, \ldots, a_n}\right)$

$\mathbf b = \left({b_1, b_2, \ldots, b_n}\right)$

When $n = 1$, the vector space degenerates to:

$\mathbf a + \mathbf b = \left({a + b}\right)$

$\lambda \cdot \mathbf a = \left({\lambda \times a}\right)$

where:

$\mathbf a, \mathbf b \in \R$

$\lambda \in \R$

$\mathbf a = \left({a}\right)$

$\mathbf b = \left({b}\right)$

Thus it can be seen that the vector space $\left({\R^1, +, \cdot}\right)$ is identical with the Field of Real Numbers denoted by $\left({\R, +, \times}\right)$.

$\blacksquare$

Also see

• Properties of the Real Numbers

Sources

• Seth Warner: Modern Algebra (1965)... (previous)... (next): $\S 26$: Example $26.2$