Definition:Permutable Subgroups

Definition
Let $\struct {G, \circ}$ be a group.

Let $H$ and $K$ be subgroups of $G$.

Let $H \circ K$ denote the subset product of $H$ and $K$.

Then $H$ and $K$ are permutable :
 * $H \circ K = K \circ H$

Also see

 * Subset Product of Subgroups: $H \circ K$ is itself a subgroup of $G$ $H$ and $K$ are permutable.