− v u 4 + u 4 − v 2 u 3 + 5 v u 3 − 3 u 3 + 3 v 2 u 2 − 7 v u 2 + 3 u 2 − 3 v 2 u + 5 v u − u + v 2 − v {\displaystyle -vu^{4}+u^{4}-v^{2}u^{3}+5vu^{3}-3u^{3}+3v^{2}u^{2}-7vu^{2}+3u^{2}-3v^{2}u+5vu-u+v^{2}-v}
