( v 4 − v 3 + v 2 − v + 1 ) ( u v − u + 1 ) ( u v − v + 1 ) u v 3 {\displaystyle {\frac {\left(v^{4}-v^{3}+v^{2}-v+1\right)(uv-u+1)(uv-v+1)}{uv^{3}}}}
