 p-adic integer

For a prime number $p$, the ring of p-adic integers is the inverse limitEvery p-adic integer has a unique convergent expansion ${\sum }_{j\ge 0}{b}_j{p}^j$ with $0\le b_j<p$. It is a complete discrete valuation ring with uniformizer $p$ and residue field ${\mathbb{F}}_p$.