Definition:P-adic Valuation/Integers

Definition
Let $p \in \N$ be a prime number. Consider the mapping $\nu_p^\Z: \Z \to \N \cup \left\{{+\infty}\right\}$ defined by:


 * $\nu_p^\Z \left({n}\right) := \begin{cases}

+\infty & : n = 0 \\ \sup \left\{{v \in \N: p^v \mathbin \backslash n}\right\} & : n \ne 0 \end{cases}$

where:
 * $\sup$ denotes supremum
 * $p^v \mathbin \backslash n$ expresses that $p^v$ divides $n$.

The mapping $\nu_p^\Z$ is called the $p$-adic valuation (on $\Z$).

Also known as
As the $p$-adic valuation is usually defined as its extension $\nu_p^\Q$ to the rationals, the $p$-adic valuation on $\Z$ is often seen referred to as the restricted $p$-adic valuation.

Also see

 * P-adic Valuation on Integers is Valuation


 * P-adic Valuation is Well Defined