 +\int_{z=x}^{0-{\varepsilon}-y}F\downharpoonright_{B_{xyz}} +\int_{z=0-{\varepsilon}-y}^{0+{\varepsilon}-x}F\downharpoonright_{C_{xyz}} + \int_{z=0+{\varepsilon}-x}^{0/0+{\varepsilon}}F\downharpoonright_{S_{xyz}}+ \int_{