Let GG be a with identity element ee. The trivial subgroup of GG is the {e}\{e\}.

Examples
  • In (Z,+)(\mathbb{Z},+), the trivial subgroup is {0}\{0\}.
  • In (R×,×)(\mathbb{R}^{\times},\times), the trivial subgroup is {1}\{1\}.
  • In any permutation group, the trivial subgroup consists of the identity permutation only.
Remarks

The trivial subgroup is the smallest subgroup of GG (by inclusion). It appears as an endpoint in definitions such as that of a .