(related to Corollary: Rules for Exponentiation in a Group)

- The rule follows immediately from the definition of exponentiation in a group, the associativity of the operation "$\ast$" and the associativity of adding integers.

- These rules require in addition the commutativity of the operation "$\ast$" and follow from the commutativity of adding integers.

- The rule is only a special notation for the rule $(3)$, since $$\frac{x^n}{y^n}=x^n\ast y^{-n}=x^n\ast (y^{-1})^n=\left(x\ast y^{-1}\right)^n.$$∎

**Forster Otto**: "Analysis 1, Differential- und Integralrechnung einer Veränderlichen", Vieweg Studium, 1983