\left(\int_{x=0/0}^{0{\varepsilon}} \int_{y=0}^{0-{\varepsilon}-x} + \int_{x=0{\varepsilon}}^{0/0+{\varepsilon}/0}\int_{y=x-0{\varepsilon}}^{0-{\varepsilon}-x} \right) \left(\int_{z=0}^{y}F\downharpoonright_{A_{yzx}}+\int_{z=y}^{0-{\varepsilon}-x}F\downharpoonright_{A_{zyx}} +\int_{z=0-{\varepsilon}-x}^{x}F\downharpoonright_{B_{zyx}} 