3-adic number
= 3-adic number
{title2=$\mathbb Q_3$}
A 3-adic number belongs to the completion of $\mathbb Q$ for the <p-adic absolute value> with prime three. Its nonzero elements have the form $3^k u$, with $k\in\mathbb Z$ and $u\in\mathbb Z_3^\times$. The <cube-class group of the 3-adic numbers> is generated by the classes of $3$ and $4$.