Groups of order 4
This article gives information about, and links to more details on, groups of order 4
See pages on algebraic structures of order 4| See pages on groups of a particular order
The classification can be done by hand using multiplication tables, but it also follows more generally from the classification of groups of prime-square order.
See also groups of prime-square order for side-by-side comparison with the situation for other primes.
The groups are:
|Group||GAP ID (second part)||Defining feature|
|cyclic group:Z4||1||unique cyclic group of order 4|
|Klein four-group||2||unique elementary abelian group of order 4; also a direct product of two copies of cyclic group:Z2.|