Definition
Alternating group A_2
Even permutations of 2 letters under composition.
The alternating group consists of the even permutations of , with composition as multiplication.
Order and simplicity
Its order is . There is only the identity; the trivial group is not simple.
References
- J. S. Milne, Group Theory, v4.01, §4, symmetric and alternating groups; Theorem 4.33 and Remark 4.34, p. 69.