$$\left. \begin{array} { l } { 1 \times 4 } \\ { m ^ { 2 } - n ^ { 2 } , m ^ { 4 } - n ^ { 4 } , m ^ { 6 } - n ^ { 6 } } \end{array} \right.$$
$-4\left(m^{4}-n^{4}\right)\left(-\left(mn\right)^{2}+\left(m^{2}+n^{2}\right)^{2}\right)$
$4,\ m^{2}-n^{2},\ m^{4}-n^{4},\ \left(m^{2}-n^{2}\right)\left(-\left(mn\right)^{2}+\left(m^{2}+n^{2}\right)^{2}\right)$
