Definition:Invertible Fractional Ideal

Definition
Let $R$ be an integral domain with fraction field $K$.

Let $I\subseteq K$ be a fractional ideal of $R$.

Then $I$ is invertible there exists a fractional ideal $J\subseteq K$ such that their product is the unit ideal of $R$:
 * $IJ = (1)$

Also see

 * Definition:Dedekind Domain