− v 4 u 4 + 2 v 3 u 4 − v 2 u 4 + v 4 u 3 − 6 v 3 u 3 + 6 v 2 u 3 − v u 3 + 5 v 3 u 2 − 11 v 2 u 2 + 5 v u 2 − v 3 u + 6 v 2 u − 6 v u + u − v 2 + 2 v − 1 {\displaystyle -v^{4}u^{4}+2v^{3}u^{4}-v^{2}u^{4}+v^{4}u^{3}-6v^{3}u^{3}+6v^{2}u^{3}-vu^{3}+5v^{3}u^{2}-11v^{2}u^{2}+5vu^{2}-v^{3}u+6v^{2}u-6vu+u-v^{2}+2v-1}
