This ring, denoted or , is defined as the quotient of the ring of integers by the multiples of .
Note that the symbols and are also used for the additive group of this ring, which is the cyclic group of order four.
|additive group||cyclic group:Z4||(4,1)|
|multiplicative group||cyclic group:Z2||(2,1)|
|general linear group of degree two||general linear group:GL(2,Z4)||(96,195)|
|special linear group of degree two||special linear group:SL(2,Z4)||(48,30)|
The ring can be defined using GAP's ZmodnZ function: