Powers of Group Elements/Product of Indices

Theorem
Let $\struct {G, \circ}$ be a group whose identity is $e$.

Let $g \in G$.

Then:
 * $\forall m, n \in \Z: \paren {g^m}^n = g^{m n} = \paren {g^n}^m$

Additive Notation
This can also be written in additive notation as:

Proof
All elements of a group are invertible, so we can directly use the result from Index Laws for Monoids: Product of Indices:


 * $\forall m, n \in \Z: g^{m n} = \paren {g^m}^n = \paren {g^n}^m$

Also see

 * Powers of Group Elements/Sum of Indices