u 4 v 2 − u 4 v − u 3 v 4 + 4 u 3 v 3 − 6 u 3 v 2 + 4 u 3 v − u 3 + 2 u 2 v 4 − 7 u 2 v 3 + 9 u 2 v 2 − 7 u 2 v + 2 u 2 − u v 4 + 4 u v 3 − 6 u v 2 + 4 u v − u − v 3 + v 2 u 2 v 2 {\displaystyle {\frac {u^{4}v^{2}-u^{4}v-u^{3}v^{4}+4u^{3}v^{3}-6u^{3}v^{2}+4u^{3}v-u^{3}+2u^{2}v^{4}-7u^{2}v^{3}+9u^{2}v^{2}-7u^{2}v+2u^{2}-uv^{4}+4uv^{3}-6uv^{2}+4uv-u-v^{3}+v^{2}}{u^{2}v^{2}}}}
