Data:L9a55/Multivariable Alexander

[math]\displaystyle{ -\frac{u v w x-u v w-u v x+2 u v-2 u w x+u w+2 u x-2 u-2 v w x+2 v w+v x-2 v+2 w x-w-x+1}{\sqrt{u} \sqrt{v} \sqrt{w} \sqrt{x}} }[/math]