Definition:Set of Residue Classes/Least Positive

Definition
Let $\left[\!\left[{a}\right]\!\right]_m$ be the residue class of $a$ (modulo $m$).

If $r$ is the smallest non-negative integer in $\left[\!\left[{a}\right]\!\right]_m$, then $0 \le r < m$ and $a \equiv r \pmod m$ from Congruence to an Integer less than Modulus.

Then $r$ is called the least positive residue of $a$ (modulo $m$).

Also known as
Some sources call this the common residue.

Also see

 * Least Absolute Residue