# Monomorphism from Rational Numbers to Totally Ordered Field

## Theorem

Let $\struct {F, +, \circ, \le}$ be a totally ordered field.

There is one and only one (ring) monomorphism from the totally ordered field $\Q$ onto $F$.

Its image is the prime subfield of $F$.

## Proof

Follows from:

Characteristic of Ordered Integral Domain is Zero
Order Embedding between Quotient Fields is Unique.

$\blacksquare$