A unit ring is a ring with a multiplicative identity. It is therefore sometimes also known as a "ring with identity."
It is given by a set together with two binary operators satisfying the following conditions:
1. Additive associativity: For all ,
,
2. Additive commutativity: For all ,
,
3. Additive identity: There exists an element such that for all
,
4. Additive inverse: For every , there exists a
such that
,
5. Multiplicative associativity: For all ,
,
6. Multiplicative identity: There exists an element such that for all
,
,
7. Left and right distributivity: For all ,
and
.