Dual quaternions may be used to perform combined rotations and translations in a single dual quaternion product operation.
Translation is performed by placing the displacement, $d$ in vector of the dual with a unit real, $\bf{d}$ $=1 + d\varepsilon$; rotation is performed as normal with the rotation vector, $r$ being placed in the non-dual vector, $\bf{r}$ $= r + 0\varepsilon$. The products of these two numbers can be used to perform either a rotate-then-translate
$\bf{q} = \bf{d \cdot r}$,
or translate-then-rotate operation,
$\bf{q} = \bf{r \cdot d}$,
on a point, $p$, which is in the vector of the dual, $\bf{p}$ $=1 + p\varepsilon$,
$\bf{p}' = \bf{q \cdot p \cdot q^*}$.
The vector of the dual of $\bf{p}'$ then contains the transformed point.
This is suggestive that a similar approach could be used with dual complex numbers for transformations on the plane. However, using this approach does not result in the correct transform for the rotate-then-translate case.
The dual quaternion case is discussed here and the dual complex case here.
Is there something I am missing here or am I correct that the product approach analogous to that using dual quaternions is not possible with dual complex numbers?
(A pending pull request to add dual complex and dual quaternion numbers is the reason for this question. It and examples of the transforms shown here are here).